Heat pump HVAC in Colorado?

[Rfsmith48]

Folks:

I have a 50 year old house in Boulder CO. With a 50 year old gas furnace....
Heating degree days here are about 5600.

The local utility has been promoting heatpump HVAC systems for homes. With rebate incentives.

BUT....None of the local contractors I have talked with want to quote Heatpump systems. (?)
Typical comments are: “We can quote that, but the supplemental electric heat draws a lot of power, and is therefore very expensive.”

Questions:

Are there good reasons why none of the local contractors are interested in quoting a heatpump system? (Other than alleged costs.)
Do any of the hardware suppliers sell a natural gas supplementary system for heat pump systems...say about 30000 BTUs?

Thanks,
Rog

 

[WorthFlorida]

Do you already have a central air system and forced warm air. Does the AC coil sit on top of the furnace in the duct work or a factory built unit. This is an example. If you want to replace the entire system, this is the type of setup you can use. When the set temperature of the thermostat and outside temperatures can determine when the AUX heat (2nd stage, gas furnace) is needed, the gas system will turn on. During mild weather when needing heat, HP is usually enough. 2nd stage does not have to be electric elements. Go on line and search on "gas furnace with heat pump coil". When you find one that looks right for you, contact the manufacture or search on their company website for dealers or distributors to find a local contractor.

Heat pumps should be everywhere by now, In South Florida, AC only units are prevalent, here in Central Florida and north, heat pumps are the norm. With big influx of mini split units of the last decade and every mini split manufactured are heat pump systems, most contractors and users are seeing a big advantage with HP.

Google Search "tax credit for heat pump 2022".

 

[Sponsor]

 

[Rfsmith48]

Thanks, will do.
Rog

 

[Fitter30]

One problem is such a small btu furnace to move enough air for your cooling load. Take a pick of the outside unit or the btu rating. 30k is what is your furnace now? Found a 45 k input 80% 3 tons of ac.Looking at average low temps 22° seems warm for me but heat pumps can handle that.

Blueridge BG801UH045AE12 45,000 BTU Furnace, 80% Efficiency, Single-Stage Burner, 1,200 CFM Multi-Speed Blower, Upflow/Horizontal Flow Application

www.alpinehomeair.com

 

[Taylorjm]

Check your cost of the system and the rebates. The tax rebates being bragged about by the president usually only apply if you are removing a gas appliance for an electric appliance, and the rebates aren't that great. If you are putting in a heat pump, and supplementing with a gas furnace you wouldn't qualify for a tax rebate. Usually the HP equipment greatly outweighs the rebate compared to a new gas furnace. In many cases I've seen a HP is 2x as much as just replacing the gas furnace and ac unit but depends on your area. Like it was mentioned, people in florida can use a HP much longer than you can in Colorado and I can in Michigan. One thing we looked at was even if a heat pump was the way we wanted to go, with the increased cost, there are rare instances where we lose power in winter. A portable generator can easily power most appliances including a gas furnace, but you would need a rather big generator to power a HP unit and most likely a portable unit couldn't handle it.

 

[Rfsmith48]

Hey Taylorjm,
Thanks for the response.
What is the furnace rating that addresses the ability of the furnace to support the square footage of a house? Our house is about 1800 sq ft.
And is there a "rule of thumb" that is useful for comparing the furnace blower rating to the house size?
Thanks again,
Rog

 

[WorthFlorida]

For proper sizing of equipment, a tool called Manual J is used. This site has a basic program for a good ball park figure and a good contractor should do their own. With a 50 year old unit, a new furnace and AC-HP maybe in order. At least for air conditioning, the efficiency has greatly improved.

Though new gas furnaces (not tankless boilers) efficiencies have not changed much, most are only around 82-83% range, however, a fifty year old unit the efficiency has dropped. Another issue can be old units do degrade and there could be holes in the plenum allowing CO to enter the home. I would get a CO detector for the home and there are some that plug into a wall outlet. If you hadn't had your gas furnace checked out and before the real cold sets in, have a service company look it over. Good one should have a camera to look into the plenum or at least open it up a bit to nspect it.

https://www.loadcalc.net

 

[Taylorjm]

For proper sizing of equipment, a tool called Manual J is used. This site has a basic program for a good ball park figure and a good contractor should do their own. With a 50 year old unit, a new furnace and AC-HP maybe in order. At least for air conditioning, the efficiency has greatly improved.

Though new gas furnaces (not tankless boilers) efficiencies have not changed much, most are only around 82-83% range, however, a fifty year old unit the efficiency has dropped. Another issue can be old units do degrade and there could be holes in the plenum allowing CO to enter the home. I would get a CO detector for the home and there are some that plug into a wall outlet. If you hadn't had your gas furnace checked out and before the real cold sets in, have a service company look it over. Good one should have a camera to look into the plenum or at least open it up a bit to nspect it.

https://www.loadcalc.net

Why are you saying gas furnaces are only in the 82-83% efficiency range? You would have to really cheap out to get one that low. Most new units are in the 95%+ efficiency range.

 

[Jadnashua]

Some of the newer heat pumps can produce useful heat down to a -20F, so aux heating isn't needed very often.

Aux heat can be an energy hog, so you need to check your costs.

The older rule of thumb x BTUs per sqft is not very accurate at all. Take two houses, one with good, tight, low-R windows, proper insulation, and well-done air sealing then compare it to a house with single pane windows, and maybe literally no insulation, and their heating and cooling loads will be vastly different.

There are ways to figure your heating load with your gas bill and the local heating degree days if you can isolate out say water heating, cooking, and maybe a gas dryer. A good estimate on that would be your gas usage during the middle of summer, then the usage during a heavy heating month in the winter. The difference would be fairly accurate of the actual energy required to heat YOUR house. Calculations often make some generalizations, actual energy used is more accurate. You'd need to know the efficiency of your existing furnace, as some of the energy in is going up the flue rather than heating the home.

 

[John Gayewski]

If you want a house that stays 70 without making air that feels warm go for it. A heat pump can effeciantly keep a house warm, but your comfort will not be the same. 70 degree air feels cold most of the objects in your house may be 70 degrees but put your hands on them... Not so comfy. Warm air or warm water feels nice becuse it's warmer than your skin. Personally saving a little money doesn't beat feeling comfortable at home.

If you ask a heat pump owner that is honest they will say the thermostat says satisfied, but we don't. For cooling they are great.

 

[Rfsmith48]

Folks,

This forum item has morphed from: "Help me find a heat pump system" to "Help me find the appropriate new furnace" since my AC system is only about 6 years old and works fine. (AC unit and coil are standard Lennox items.)

The local library has found me a copy of Manual J. After reviewing the Manual J, I need some guidance on how to apply it: I need to verify that the contractors have selected the appropriate sized furnace. Which sections of Manual J will help with those calculations?

Thanks again.

Rog Smith

 

[John Gayewski]

Folks,

This forum item has morphed from: "Help me find a heat pump system" to "Help me find the appropriate new furnace" since my AC system is only about 6 years old and works fine. (AC unit and coil are standard Lennox items.)

The local library has found me a copy of Manual J. After reviewing the Manual J, I need some guidance on how to apply it: I need to verify that the contractors have selected the appropriate sized furnace. Which sections of Manual J will help with those calculations?

Thanks again.

Rog Smith

Slant fin has a heat loss app. You can input your homes info into it and get a good number for each room. There is another way to do it by clocking your meter, but this doesn't give you a room by room number.

 

[Jadnashua]

A system set up for cooling will tend to have the air volume/speed set fairly high as the moving air helps to make you feel cooler. A heat pump often doesn't heat the coil as hot as it would be with a gas fired burner, so the outlet air will end up cooler with the higher air velocity. What you need is to slow the air down so that it can pick up more heat, and you don't get the wind chill effect to be comfortable. A better engineered system will slow the fan down when heating is called for versus cooling.