VERMONT BASELESS CLAIMS ABOUT COLD CLIMATE HEAT PUMPS FOR BUILDINGS

The Vermont Comprehensive Energy Plan, CEP, projects to install about 35,000 cold-climate heat pumps, ccHPs, by 2025 to begin the transformation of about 63% of building heating to renewable electricity by 2050. About 34% would be by biomass (wood burning) and bio liquids, and only about 3% would be by fossil fuels. See page 8 of URL

https://outside.vermont.gov/sov/webservices/Shared%20Documents/2016...

 

As a result, Vermont State government is subsidizing a ccHP program for residential and other buildings, which could not be successful (reducing annual energy costs and CO2eq), unless at least 80% of all Vermont buildings had deep retrofits. This surely was known before the program was started, but RE rah-rah and subsidies got the program going anyway. 

 

It is downright criminal for the state government, GMP, VT-DPS, VPIRG, VEIC, Efficiency Vermont, Efficiency Vermont-approved contractors, etc., to obfuscate the drawbacks of ccHPs and use subsidies (extorted from other ratepayers and taxpayers) to cajole Vermonters to have ccHPs, when it is abundantly clear, the annual energy cost savings are more than wiped out by: 

 

- Annual lease payments to utilities, such as GMP. See Appendix for details

- Annual cost of amortizing invested capital, at 5%/y for 15 years

- Annual maintenance contract fees, at about $200/y, not all parts covered

- Annual costs for unscheduled outage/service calls, at about $150/call, no parts

 

The heat pumps for houses mainly are cold climate, ductless, mini-split units that have a heating/cooling unit mounted on an indoor wall and a ground-mounted compressor unit adjacent to the building. Heat pumps work best in houses with open floor plans on the downstairs floor, i.e., kitchen/living/dining is one big room. Almost all mini-split heat pumps are imported from Japan and Korea, i.e., adds to the US trade deficit and sends money out of Vermont.

Vermont Heat Pump Program a Failure Due to a lack of Energy Cost Savings

After numerous complaints about a lack of energy savings, the Vermont Department of Public Service surveyed 77 existing heat pump installations at 65 locations and found the average energy savings were $200/heat pump/y, which had an installed cost of $5000/heat pump, and might last up to 15 years. Amortizing the $5000 at 5% over 15 years requires monthly payments totaling $474/y.

 

Heat pumps used in typical Vermont houses are money losers, because the annual amortizing costs, maintenance contracts, and service calls of heat pump plus back-up systems would much more than offset the insignificant energy cost savings.

 

Vermont Mix House

 

“Vermont mix houses” (a mix of older and newer houses) are energy hogs. They would have a high peak heating demand during colder winter days, which makes them unsuitable for heat pumps. In this article a “Vermont mix house” is assumed to be a 2000 sq ft house requiring about 64000 Btu/h at -20F outdoors and 65F indoors.

 

At 0F and below, the hourly cost of heating a “Vermont mix house” with heat pumps + fuel oil back-up system is higher than with only a fuel oil back-up system. See table 2A

 

Heat pumps used in a “Vermont mix house” would displace only about 32% of the fossil Btus, which would provide inadequate energy cost savings and CO2 emissions reduction. See table 3

 

Highly Insulated/Highly Sealed House

 

“HI/HS houses” likely would have R20 basements, R40 walls, R60 roofs, R7 triple pane windows, R8 insulated doors, and less than 1.0 ACH @ 50 Pascal. See below Blower Door Test. They would have a low peak heating demand during colder winter days, which makes them suitable for heat pumps. In this article an “HI/HS house” is assumed to be a 2000 sq ft house requiring about 17045 Btu/h at -20F outdoors and 65F indoors.

 

At 0F and below, the hourly cost of heating an “HI/HS house” with only heat pumps is higher than with only a fuel oil back-up system.

 

Heat pumps used in an “HI/HS house” would displace 100% of the fossil Btus, which would provide adequate energy cost savings and CO2 emissions reduction. See table 3

 

Such houses likely would have a propane-fired stove (thermostat-operated/no electricity), but not a much more expensive fuel oil system, in case of a power failure. See table 2B and Appendix

Blower Door Test: A well-insulated/well-sealed house, tested with a blower door at 1.5 whole-house air changes per hour, ACH, at 50 pascal negative pressure, would have average natural ventilation of about 0.15 ACH, much less than the recommended minimum of 0.5 ACH. *

 

However, that is not relevant, because the house would have an HVAC system, with supply and return ductwork to each room, to supply a minimum of 0.5 ACH to the house for health reasons.

The house would have with an air-to-air heat exchanger to transfer the Btus of the stale exhaust air to fresh incoming air.

Available models have 85% efficiency, i.e., very few Btus are lost.

The house could have a HEPA filter to filter the fresh incoming air.

 

* The fan of the blower door sucks air out of the house (doors, windows, etc., closed) to create a negative pressure of 50 pascal. After that is achieved, a smoke wand is used to detect the various leaks to be sealed.

One pascal = 0.2 inches of water column; 50 pascal x 0.2 = 10 inches of water column.

 

Peak Space Heating Demands of Various Houses 

 

Typical space heating demands of 2000 ft2, freestanding houses are shown in table 1. It appears only houses with 3.0 ACH or less are suitable for heating with air source heat pumps. All the rest of the houses are unsuitable. The peak heating demands are too high.

 

All of this has been known for about 20 years, so it should not be a surprise to find owners who installed heat pumps in their typical, energy-hog houses to reduce their energy bills, end up having no or minimal energy cost savings, as was found by this Vermont Department of Public Service study.

https://publicservice.vermont.gov/sites/dps/files/documents/Energy_...

 

Passivhaus, the Gold Standard for Energy Efficiency

 

The Passivhaus standard, formulated in Germany, dates from the mid 1980s.

A free-standing Passivhaus, 2000 ft2, maximum heating demand 10 W/m2 x 186 m2 = 1.86 kW, or 6,348 Btu/h, or 3.2 Btu/ft2/h applies to all climate zones; for climate zone 6 the heating demand would be at -20F outdoors and 65F indoors.

A 2 kW, thermostat-controlled electric heater in the air supply duct could be the heating system!

No expensive GSHP or ASHP system is required!!

 

The house, tested with a blower door at 0.6 ACH, at -50 pascal, would have average natural ventilation of about 0.06 ACH, much less than the recommended minimum of 0.5 ACH.

 

However, that is not relevant, because the house would have an HVAC system, with supply and return ductwork to each room, to supply a minimum of 0.5 ACH to the house for health reasons.

The house would have with an air-to-air heat exchanger to transfer the Btus of the stale exhaust air to fresh incoming air.

Available models have 85% efficiency, i.e., very few Btus are lost.

The house could have a HEPA filter to filter the fresh incoming air.

 

Typical space heating demands of 2000-ft2, free-standing Vermont houses are shown in table 4.

 

Table 4/Vermont	Built		Area	Heat Demand	Peak Demand	Air Leakage	ACH
		%	ft2	Btu/ft2/h	Btu/h	ft3/min	-50 pascal
Typical older house	1750 - 1990	68.4	2000	40.0	80,000	2667	10.0
Newer house	1990 - 2000	10.0	2000	24.0	48,000	1600	6.0
Newer house, IECC	2000 - 2012	10.0	2000	20.0	40,000	1867	7.0
.
Newer house, IECC	2012 - 2021	10.0	2000	15.0	30,000	800	3.0
“HI/HS house”	2000 - present	1.5	2000	8.5	17,000	400	1.5
Passivhaus	1985 - present	0.1	2000	3.2	6,348	160	0.6
		100.0

NOTE:

Furnace capacity is about equal to peak heating demand / efficiency.

Heat in a gallon of fuel oil is the higher heating value, HHV, as purchased.

Not all of that heat is available after combustion, due to energy for H2O formation.

If wood, its moisture content requires heat to evaporate the moisture

Lower heating value, LHV = HHW - energy for moisture evaporation.

Only the LHV of the fuel is available for space heating.

Only the LHV should be used for efficiency calculations.

http://www.virginiaradiant.com/whitepages/LowHeatvalue-HighHeatValu...

VT-DPS Survey of Owners with Heat Pumps

 

The VT-DPS survey showed heat pumps are operated only a few hours at 0F and below, i.e., almost all owners are relying on only their back-up systems on cold days. See figure 14 of URL

https://publicservice.vermont.gov/sites/dps/files/documents/Energy_...

 

The surveyed Vermont houses with heat pumps likely are slightly better insulated and sealed than the “Vermont mix” house, i.e., they would have greater than 32% of fossil Btu displacement.

 

NOTE:The CEP projects about 80% to 90% fossil Btu displacement by 2050, which clearly is an impossibility without building thousands of NEW HI/HS buildings per year all over Vermont to replace energy-hog buildings, PLUS “deep retrofitting” almost all of the remaining buildings. See Appendix.

Balance Point of Peak Heating Demand and Heat Pump Capacity

 

As the outdoor temperature decreases, the building heating demand increases, but the heat pump capacity to provide heat decreases.

At a certain temperature, the balance point, demand is equal to capacity.

For temperatures below the balance point, the house needs supplemental heat from the back-up system.

Balance points are about 18F for a mix of older and newer houses in Vermont, i.e., the so-called “Vermont mix”.

NOTE: Figure 9 of URL confirms:

 

1) Heat pump output starting to decrease at about 18F, and

2) Output decreasing further as outdoor temperatures decrease, and

3) At the same time, as building heating demand is increasing with lower and lower outdoor temperatures, more and more heat is provided by the back-up system.

https://publicservice.vermont.gov/sites/dps/files/documents/Energy_...

 

Table 2 demonstrates balance points for a 2000 sq ft “Vermont mix” house and a 2000 sq ft HI/HS house. See table 4.

 

- The HI/HS house gets 100% of its heat from heat pumps at -20F. In case of a power failure, a propane stove or wood stove would be required.

 - The “Vermont mix” house, with the same heat pump complement, gets only a small percentage* of its heat from heat pumps, with the rest from the back-up system.

- Generally, it is less costly to operate only the back-up system starting at about 0F, because of low coefficients of performance of the heat pumps, i.e., high kWh/delivered Btu.

- A COP = 1.0 is equivalent to electric heating

* In a below section it is shown the "small percentage" is about 32%

https://www.energyvanguard.com/blog/36683/Finding-Balance-Heat-Pump...

 

Table 2	HI/HS house	HI/HS house	HI/HS house	"VT mix" house	“VT mix” house	COP
Area, sq ft	1232	2000	2000	2000	2000
	Heat pump	Heat pump			Suppl. System
	Capacity	Capacity	Heat demand	Heat Demand
Outdoor, F	Btu/h	Btu/h	Btu/h	Btu/h	Btu/h
65			0	0	0
47	19000	30844	3610	13553	0	4.16
47	26112	42390	3610	13553	0	3.20
Balance @ 18F		35389	9500	35389	0	2.98
17	11394	18496	9625	36141	17645	2.97
17	19204	31176	9625	36141	4965	2.43
5		27860	12032	45176	17316	2.20
0	17610	28588	13035	48941	20353	2.10
-7	14396	23371	14438	54212	30841	1.97
-10	13304	21597	15040	56471	34874	1.20
Balance @ -20F	10500	17045	17045	64000	46955	1.10

HI/HS House Energy Cost per Hour

The HI/HS house heating demand served by a heat pump system is less costly per hour than by a fuel oil system, except on very cold days, i.e., about 0F and below.

 

Defrost cycles start about 32F and increase in frequency and length, up to 15 minutes, with colder outdoor temperatures. During defrost, no heat is delivered to the house.

 

HHV, higher heating value, is the purchased fuel

LHV, lower heating value, is less than HHV, due to the evaporation of water from hydrogen burning,

2H2 + O2-->2H2O. That heat disappears up the chimney.

See table 2A and 3.

 

Table 2A		HHV	LHV	Efficiency
Fuel oil, $/gal	3.1	138490	128488	0.78
Propane, $/gal	2.3	91420	84250	0.85
Wood, $/cord	300			0.60
Wood, million Btu/cord	15.3
Electricity cost, $/kWh	0.19
.
Metered consumption, kWh	1730	See table 3
Used for heating, kWh	1560
Standby/defrost loss, kWh	170
Ratio, 1730/1560	1.109
.
Table 2A	Heat pump	HI/HS	HI/HS	HI/HS	COP
Area, sq ft	Capacity	2000	2000	2000
		Heat	Heat pump	Fuel oil
		Demand	Cost	Cost
Outdoor, F	Btu/h	Btu/h	$/h	$/h
65		0	0	0
47	30844	3610	0.054	0.112	4.16
47	42390	3610	0.070	0.112	3.20
18	35389	9500	0.197	0.294	2.98
17	18496	9625	0.200	0.298	2.97
17	31176	9625	0.245	0.298	2.43
5	27860	12032	0.338	0.372	2.20
0	28588	13035	0.383	0.403	2.10
-7	23371	14438	0.453	0.447	1.97
-10	21597	15040	0.774	0.465	1.20
Balance @ -20F	17045	17045	0.957	0.527	1.10

“Vermont Mix” House Energy Cost per Hour

 

The “Vermont mix” house heating demand served by the heat pump system is less costly than by a fuel oil system, except on very cold days, i.e., about 0F and below. On those days, it is more economical to turn off the heat pump system and operate only the fuel oil system. Similar comparisons can be made for propane and wood. The standby/defrost loss is 2085/1880 = 1.109. See Table 2B and 3

 

Metered, kWh	2085	See table 3
Used for heating, kWh	1880
Standby/defrost loss, kWh	195
Ratio, 2085/1880	1.109
.
Table 2B		"VT mix"	"VT mix"	"VT mix"	"VT mix"	"VT mix"	"VT mix"	COP
Area, sq ft		2000	2000	2000	2000	2000	2000
	Heat pump	Heat	Heat Pump	Fuel oil	Fuel oil	Total	Fuel oil only
	Capacity	Demand	Cost	Demand	Cost	Cost	Cost
Outdoor, F	Btu/h	Btu/h	$/h	Btu/h	$/h	$/h	$/h
65		0	0	0	0	0	0
47	30844	13553	0.201	0	0	0.201	0.419	4.16
47	42390	13553	0.262	0	0	0.262	0.419	3.20
Balance @ 18F	35389	35389	0.733	0	0	0.733	1.095	2.98
17	18496	36141	0.385	17645	0.546	0.930	1.118	2.97
17	31176	36141	0.792	4965	0.154	0.946	1.118	2.43
5	27860	45176	0.782	17316	0.536	1.318	1.397	2.20
0	28588	48941	0.841	20353	0.630	1.470	1.514	2.10
-7	23371	54212	0.733	30841	0.954	1.687	1.677	1.97
-10	21597	56471	1.111	34874	1.079	2.190	1.747	1.20
-20	17045	64000	0.957	46955	1.452	2.409	1.980	1.10

Comparison of "Vermont Mix" House and HI/HS House

A 2000 sq ft "Vermont mix" house and a 2000 sq ft HI/HS house are compared in table 3.

- The analysis shows about 32% of heating is by heat pumps, 68% is by back-up systems for a "Vermont mix" house 

- Both houses have the same complement of heat pumps.

- The "Vermont mix" house has a back-up system with its own furnace maintenance contract (at least $300 per year with not everything covered), its own balance of system maintenance and outage service calls, and its own amortization. Those costs are not shown in table 3.

 

https://afdc.energy.gov/fuels/fuel_comparison_chart.pdf

https://www.myamortizationchart.com/15-year/5000-dollars/5_00-percent/

https://publicservice.vermont.gov/sites/dps/files/documents/Energy_...

Table 3/No Heat pump	Fuel oil	Propane	Wood	Fuel oil	Propane	Wood
Peak demand, Btu/h	64000	64000	64000	17045	17045	17045
Fuel, gal or cord	600	840	6.6	160	224	1.7
Fuel cost, $/gal	3.1	2.3		3.1	2.3
Wood, $/cord			300			300
Wood, million Btu/cord (dry)			15.3			15.3
Electricity cost, $/kWh	0.19	0.19	0.19	0.19	0.19	0.19
Annual fuel cost, $/y	1860	1931	1965	495	514	523
HHV	138490	91420		138490	91420
LHV	128488	84250		128488	84250
Efficiency	0.78	0.85	0.60	0.78	0.85	0.60
Heat to building, Btu/y	60132384	60132384	60132384	16014945	16014945	16014945
.
With Heat pump	Fuel oil	Propane	Wood	Fuel oil	Propane	Wood
Consumption, kWh/y	2085	2085	2085	1730	1730	1730
Output, million Btu/y	21.4	21.4	21.4	17.8	17.8	17.8
COP	3.0	3.0	3.0	3.0	3.0	3.0
Standby loss, kWh/y	76	76	76	63	63	63
Defrost loss, kWh/y	129	129	129	107	107	107
Heat to building, kWh/y	1880	1880	1880	1560	1560	1560
Heat to building, Btu/y	19295923	19295923	19295923	16014945	16014945	16014945
Displaced fuel, %	0.32	0.32	0.32	1.00	1.00	1.00
Supplement fuel, Btu/y	40836461	40836461	40836461
Fuel, gal or cord/y	407	570	4.4
Fuel, cost, $/y	1263	1312	1335
Electricity cost, $/y	396	396	396	329	329	329
Total energy cost, $/y	1659	1708	1731	329	329	329
Energy cost savings, $/y	201	224	234	167	186	195
Capital cost, $	10000	10000	10000	10000	10000	10000
Useful life, y	15	15	15	15	15	15
Amortize at 5%, $/y	948	948	948	948	948	948

Capital Cost of Heat Pumps

 

As a rough estimate, you can expect an air-source, mini-split heat pump installation to cost between $3,500 and $5,000/heat pump (turnkey). Central heat pump systems (with supply and return ducts to each room) cost between $12,000 and $20,000. Depending on where you live and the type of air source heat pump technology you’re installing, there may be tax credits and rebates available to decrease your upfront costs. See URL

https://www.energysage.com/green-heating-and-cooling/air-source-hea...

Average turnkey costs are about $6000/heat pump in South Burlington, Winooski and Colchester, Vermont. See URL

https://www.manta.com/cost-heat-pump-burlington-vt

 

Performance Ratings of Heat Pumps

In table 4, column 1 are average data for the mini-split, ductless, cold climate heat pumps of the VT-DPS study.

Column 5 shows the heat pump capacity of a 1232 sq ft HI/HS house

Column 6 shows the heat pump capacity of a 2000 sq ft HI/HS house, which is assumed equal to the “Vermont mix” house; it was obtained by proration.

Table 4 is based on table 6 and 15 of URL.

https://publicservice.vermont.gov/sites/dps/files/documents/Energy_...

- Heat pumps are rated at moderate compressor and fan speeds (making not much noise), at an outdoor temperature of 47F, per industry standard. Coefficients of performance, COPs, are highest. COP = thermal Btu out/electrical Btu in

- Heat pumps are rated at high compressor and fan speeds (making significantly more noise), at an outdoor temperature of 17F, so-called maximum conditions, per industry standard. COPs are lower

- Heat pumps can operate at 10F or lower, but their COPs would be lower and lower. Not only do they deliver less heat, Btu/h, but they do so inefficiently, low COPs, at exactly the same time the building needs the most heat, because it is cold and windy outside.

- Whereas heating demand increases at lower temperatures, the heat pumps contribute less and less, and the back-up systems contribute more and more. The onset of reduced heat pump percent contribution starts at about 18F. See figure 14 of URL

- Whereas, on average, "Vermont mix" houses demanded (80,000 + 48,000)/2 = 64,000 Btu/h at -20F, the heat pumps, on average, delivered only 17045 Btu/h at -20F, and did so inefficiently at a COP = 1.10. That means, during cold temperatures, the backup systems provided up to 4.5 times more heat than the heat pumps. See figure 14 of URL

- Whereas the seasonal average COP was 3.0, that average affected only 32% of the total seasonal heat.

- Some owners, not aware of the shortcomings of heat pumps at low temperatures, kept their heat pumps running anyway when it was cold outside, and turned on their existing back-up system, or wood stove, to help out, losing more money than warranted.

- It likely would be better regarding dollar savings, it they had turned off their heat pumps at about 0F and ran only their back-up systems, especially so, if their houses were poorly insulated and sealed, and if their back-up systems had low operating costs per Btu, such as a wood stove.

- The COPs in table 4 are for newly installed heat pumps. The COPs decrease with age, as is true for all systems.

NOTE: The output and COP of ground-source heat pumps remain near constant throughout the year, because the ground temperature is a constant 55F at about 6 to 8 feet below grade. Their COPs are much higher than of air source units throughout the year, i.e., heating and cooling. They should be required for all new buildings. In case of a power failure, a propane fired stove (thermostat-operated/no electricity) or wood stove would be required.

 

Table 4				1232 sq ft	2000 sq ft
Heat pump	Temp	Avg COP	Remarks	HI/HS	"Vermont mix"
Capacity	Outdoor			Capacity	Capacity
Btu/h	F			Btu/h	Btu/h
	65	5.50	Extrapolated
	55	5.00	Extrapolated
17388	47	4.16	Rated capacity	19000	30844
23897	47	3.20	Maximum conditions	26112	42390
.
10427	17	2.97	Rated capacity	11394	18496
17575	17	2.43	Maximum conditions	19204	31176
.
16116	5	2.20	Compressor and fan at high speed	17610	28588
13175	-7	1.97	Compressor and fan at high speed	14396	23371
12175	-10	1.20	Extrapolated	13304	21597
9609	-20	1.10	Extrapolated	10500	17045

Heat Pump Service Hours at Low Temperatures

 

The number of hours heat pumps are in service (right axis) versus outdoor temperature is shown in figure 9 of the URL. Based on real-world conditions of surveyed heat pump installations, figure 9 shows they start to perform much less service at about 10F to 12F and perform very little service at about 8F and below, about 400 hours of the heating season.

https://publicservice.vermont.gov/sites/dps/files/documents/Energy_...

Almost all households with heat pumps would turn on their back-up systems at outdoor temperatures of about 18F and below, especially on windy days, because of:

 

1) The excessive noise of the compressor and fan.

2) The heat pump having a lower and lower COP.

3) The heating demand of typical insulated and sealed houses exceeding the output of the heat pump, i.e., it could partially keep warm the kitchen/living/dining space, but not the rest of the house.

 

If the fossil-fired back-up systems are highly efficient (85%+), or wood stoves, it is likely a money saver to run them during cold hours.

 

Heat pumps likely would cover most of the heating demand during less cold days, say 12F to 60F, which would cover the remaining hours of the heating season. See figure 9 and 14 of URL.

https://publicservice.vermont.gov/sites/dps/files/documents/Energy_...

Complaints by Owners with Heat Pumps Confirmed by VT-DPS Study

 

After many complaints by households that spent about $3000/heat pump (turnkey, less subsidies), VT-DPS performed a survey of actual heat pump installations and their performance. The study lasted from November 2015 through the spring of 2017 and examined a total of 77 heat pumps installed at 65 residential locations in Vermont. The DPS study found:

 

- Overall dollar savings are impacted by the efficiency of the back‐up fossil fuel system. The higher the efficiency of the back-up system, the smaller the amount of fuel displaced by the heat pump.

- The more hours the back-up system has to be used (during colder periods, when heat pumps cannot keep warm the house), the fewer hours are left over, during moderately cold days, for the heat pump, operating by itself, to provide savings.

- Houses with poor insulation and air leaks will get much less benefit from a heat pump, than owners with HI/HS houses.

- It is unlikely that a heat pump by itself would ever be sufficient to heat a typical Vermont house without use of a back-up heating system.

- The average energy saving was $200/heat pump/y, i.e., some owners had near-zero savings, or worse, and some owners had more than $200.

- Also, it is likely these maverick households have houses with slightly better insulation and sealing than the "Vermont mix" house.

 

NOTE: At least 90% of Vermont houses would not be suitable for heating only with heat pumps.

 

NOTE: The annual energy savings were grossly less than advertised by VPIRG and Efficiency Vermont, i.e., not the $1000 to $1842 per year, according to the websites of VPIRG and EV. The low savings were due to a variety of factors, the main factor being the lack of sufficient insulation and sealing. See Appendix

 

NOTE: Now these households have two heating systems, one for when it is not so cold (heat pump is efficient and sufficient to heat most of the house), and one for when it is cold (heat pump is inefficient and not sufficient to heat the house).

 

 Owners invested capital in these two heating systems, which they likely paid for with borrowed money, requiring monthly payments for 5 or 15 years. Both heating systems also have:

- Annual costs for maintenance contracts (not all costs covered) and outage service calls

- Annual energy costs for operation during their 15 to 20 year life.

 

The $200/y energy saving would not even make a small dent in those annual costs, all that courtesy of state government expensively subsidizing heat pumps as part of VT-DPS RE “policy objectives”.

 

It would have been better, if the state had boosted net-zero and energy surplus buildings these past 20 years. By now there would be many thousands of them in Vermont.

 

Overeager contractors installed heat pumps in houses that were completely unsuitable for them.

The state should get out of the energy business.

Make sure to read the VT-DPS report. It is an eye opener. See URL.

 

https://publicservice.vermont.gov/sites/dps/files/documents/Energy_...

http://www.windtaskforce.org/profiles/blogs/heat-pumps-oversold-by-...

APPENDIX 1

Deleted

APPENDIX 2

Example of Highly Insulated, Highly Sealed House

 

A small 1232 ft2, HI/HS house, open floor plan, peak space heating demand 10,500 Btu/h at -20F, or 8.5 Btu/ft2/h, is equipped as follows:

 

Heating: two Mitsubishi, Mr. Slim, ductless, mini-split, heat pumps (one downstairs @ 12,000 Btu/h, and one upstairs @ 9,000 Btu/h), installed cost about $5,250. The upstairs unit usually does not operate until the outdoor temperature decreases to about 20F.

 

Ventilation: one Lifebreath 155 ECM energy-recovery ventilator.

 

Electricity: a grid-connected, PV system, 5.7 kW, roof-mounted, with Fronius IG 5100 inverter, installed cost about $22,000 less subsidies.

 

The total rated capacity of the heat pumps is 21,000 Btu/h, the output at low temperatures likely would be 0.5 x 21,000 = 10,500 Btu/h, which, no surprise, happens to be equal to the peak heating demand!

 

Such an HI/HS house, with south facing, triple-pane windows (for passive solar heat gain), and a large, south-facing roof (for the PV system), and with a low peak heating demand, is suitable for heating with heat pumps.

 

NOTE: An equivalent 2000 ft2 house would have a peak space heating demand of about 2000/1232 x 10500 = 17,045 Btu/h at -20F. See table 5

 

http://www.greenbuildingadvisor.com/blogs/dept/musings/just-two-min...

https://www.greenbuildingadvisor.com/article/heating-a-tight-well-i...

APPENDIX 3

Deep Retrofits

Ideally, a “deep retrofit”, of an older house, at $30,000 and up, would include new R-7, triple-glaze windows (See Appendix), new R-10 doors, R-20 basement, R-40 walls and R-60 ceilings/roofs, and sealing to 1.0 air change per hour, ACH, or less, as determined by blower door tests.

 

The sealing is best done on the outside of the structure, which requires removing the siding. Because of the tight sealing, the following is required:

 

- Air supply and return ductwork to adequately ventilate all areas of the house

- Energy-recovery ventilator to strip the heat from exhaust air and transfer it to incoming fresh air

- Means to maintain humidity at required levels.

See URL for details of “deep retrofit” approaches to reduce energy consumption by buildings

https://contractors.efficiencyvermont.com/Media/Default/bbd/2018/do...

APPENDIX 4

Vermont Heat Pump Program Likely Would Fail to Meet CEP Requirements for Buildings by 2050

The CEP projects Vermont primary energy as shown in table 1. The 57% electricity for transportation, buildings and industry would require a large percentage of residential and other buildings to be HI/HS, and have a heating demand of 17045 Btu/h or less, at -20F, for a 2000 sq ft house, in order for these buildings to be heated with heat pumps without back-up systems. In case of a power failure, a propane stove (thermostat-operated/no electricity) or wood stove would be required.

http://www.windtaskforce.org/profiles/blogs/excessive-predictions-o... 

Table 1/Primary energy	2016	2016	2050	2050
	%	TBtu	%	TBtu
Gasoline E10	34.562	37.912	3.000	2.276
Diesel blend		8.818
Other energy		2.000
B100 + E100	2.133	3.007
Total, transportation	34.562	48.730
.
Fossil, buildings, industry	27.661	39.000	3.000	2.276
.
Biofuels, transportation, buildings, industry	10.117	14.264	37.000	28.076
Electricity, transportation, buildings, industry	27.661	39.000	57.000	43.252
Total	100.000	140.994	100.000	75.881

APPENDIX 5

Vermont Bio Fuel Program Likely Would Fail to Meet CEP Requirements for transportation, buildings and industry by 2050

Total bio = 3.007 + 14.264 = 17.271 TBtu in 2016

Total bio = 28.076 TBtu in 2050

Increase = 10.805 TBtu. See URL

http://www.windtaskforce.org/profiles/blogs/excessive-predictions-o...

APPENDIX 6

The Vermont Heat Pump Promotion Troika

http://www.windtaskforce.org/profiles/blogs/heat-pumps-oversold-by-... 

1) GMP: Kristin Carlson, GMP's vice president for strategic and external affairs, said in an email that the utility has now installed 1,125 heat pumps.

 

-GMP arranges for the installation with an Efficiency Vermont-approved contractor.

- The contractor chooses the heat pump brand and model; brands include Daikin, Fujitsu, and Mitsubishi, with outputs ranging from 9,000 Btu/h to 18,000 Btu/h.

- GMP loan at an interest rate is 10.74%/y. That appears to be a usury rate!

- GMP says that payments will range from $49 to $81 per month, depending on the model of heat pump that's installed.

- At $49/month, a homeowner would pay $8,820 for a single-head minisplit over the 180-month payback period.

- At $81/month, a homeowner would pay $14,580.

- That doesn't include the electricity required to run the unit.

- Should a homeowner sell the house before the loan is repaid, GMP says it can offer a buy-out price for the heat pump, or the new owner could pick up the payments.

http://www.greenbuildingadvisor.com/blogs/dept/green-building-news/...

2) Efficiency Vermont: According to a fact sheet at Efficiency Vermont, a homeowner would save:

- $1,842/y by shifting 80% of the heating load away from electric resistance heat to a cold-climate heat pump. See note

- Propane users would save $1,268/y.

- Fuel oil users would save $865/y.

- The “fact sheet” (fiction sheet?) is no longer accessible!

NOTE: Instead of Efficiency Vermont spouting phony numbers, it is best to listen to a reality-based person. Vermont Fuel Dealers Association Executive Director Matt Cota: “Most heat pumps installed in Vermont are used for air conditioning. They provide heat mostly during the shoulder seasons. When the heat pumps are “installed and used correctly,” he said, they might be able to offset as much as 30% of heating costs.” Table 3 in this article shows about 32%

“What they won’t do is replace your heating load in the middle of the winter, during the 90 coldest days of the year when you need wood, gas, fuel oil and propane in order to keep the pipes from freezing,” he said. “Unless we’re talking about a newly built, net-zero house (HI/HS house), yeah, in that case you will forego the fuel oil, but that’s not going to happen in 99% of the cases.”

http://www.greenbuildingadvisor.com/blogs/dept/green-building-news/...

3) VPIRG, an RE Lobby: VPIRG, a booster of renewable energy, mostly financed by Vermont RE businesses, estimated the annual savings of a heat pump at $1000 to $1500 on a $3000 household heating bill. It appears, VPIRG grabbed a number out of the air, because it looked good.

APPENDIX 7

The below table compares single, double and triple pane windows, glass only. Single pane tends to freeze on the inside. This is avoided with double and triple pane.

Heat transmission of double pane is 58/222 = 26% of single pane

Heat transmission of triple pane is 33/58 = 59% of double pane

The R-value, glass only, of double pane is about 3, triple pane about 5.

Triple pane should be used to reduce peak heating demand of the building to enable use of heat pumps

http://cecs.wright.edu/~sthomas/htchapter03.pdf 

 

Window	Single pane	Double pane	Triple pane
Conditions
T1amb, indoor, C	20	20	20
T2amb, outdoor, C	-10	-10	-10
Width, m	0.8	0.8	0.8
Height, m	1.5	1.5	1.5
Area, A, m2	1.2	1.2	1.2
Glass, L1, mm	8	4	4
Air, L2, mm		10	10
Glass, L3, mm		4	4
Air, L4, mm			10
Glass, L5, mm			4
k1, glass, W/m.K	0.780	0.780	0.780
k2, air, W/m.K	0.026	0.026	0.026
Film, h1, outdoor, W/m2.K	10	10	10
Film, h2, indoor, W/m2.K	40	40	40
Calculations
R1, film = 1/(h1 x A)	0.08333	0.08333	0.08333
R2, glass = L1/(k1 x A)	0.00855	0.00427	0.00427
R3, air = L2/(k2 x A)		0.32051	0.32051
R4, glass = L3/(k1 x A)		0.00427	0.00427
R5, air = L4/(k2 x A)			0.32051
R6, glass = L5/(k1 x A)			0.00427
R7, film = 1/(h2 x A)	0.02083	0.02083	0.02083
R total	0.11271	0.43323	0.75801
Q (watt) = (T1amb -T2amb)/Rtot	266	69	40
Q (watt)/m^2)	222	58	33
RSI-value = K/(watt/m^2)	0.135	0.517	0.909
R-value (glass only) = 5.67826 x RSI	0.77	2.94	5.16
T, inside glass = T1amb - Q x R1	-2.2	14.2	16.7

APPENDIX 8

HOW TO BUILD AN R-40 WALL

Existing houses typically have a sheet of 6 mil PVC behind the sheetrock and fiberglass insulation between the studs.

The cold temperatures are inside the fiberglass insulation, i.e., close to the sheetrock.

Blueboard must not be added to the exterior of the sheathing of such houses to avoid trapping moisture.

NOTE: In case of a deep retrofit (with blueboard on the outside of the sheathing), the sheetrock and PVC behind the sheetrock must be removed to avoid trapping moisture.

The R-40 Wall has the Following Layers:

0.5-inch sheetrock

2 x 6 stud wall

3 inches of open cell spray foam or open cell foam sheet between studs leaving a 2.5-inch space for wiring and piping. The open cell foam allows the wall to breathe to the interior.

0.5-inch plywood sheathing, all seams taped; no OSB

6-mil PVC vapor barrier, all seams taped

Two layers of 2 inch x 4 ft x 8ft Dow blueboard, all seams staggered and taped

1 x 3 strapping and 7”-long screws to hold blueboard to framing. This will provide a ¾ airspace between blueboard and siding

Siding mounted to strapping.