NG furnace vs modern heat pump


 
Brett-EDH

Brett-EDH

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Who has which and what’s the real cost or benefits of either?

Seeking real world input on moving to a modern heat pump system. Current heat is NG furnace and I’ll likely be updating my hvac system.

Pros, cons, pitfalls, glaring issues. Share them all please.
 
Brett-EDH said:
Who has which and what’s the real cost or benefits of either?

Seeking real world input on moving to a modern heat pump system. Current heat is NG furnace and I’ll likely be updating my hvac system.

Pros, cons, pitfalls, glaring issues. Share them all please.
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Climate matters. Where you live and the specific equipment you choose will affect performance and cost of operation...sometimes dramatically. I live in Northern NY and have used heat pumps exclusively for 4 years now with both pros and cons to show for it. FWIW - I design HVAC systems for a living and can get as deep into the discussion as you wish. Every locality has what is know as a “design day” temperature that systems are targeted towards. This is the lowest outdoor temperature at which your designed system will be able to maintain the temperature in the home. If you know this, we can go from there. If not, share your city & state and I’ll look it up for us to have a baseline to start from. Any recommendation I might have will be subject to change based on design day conditions.
 
I look forward to reading feedback from our members on this question. I'll assume not many of our members here are Refrigeration or HVAC pros, so I'll share the following site in case you want to pose the same question where there are several pro members: https://www.diychatroom.com/forums/hvac.17/

I've never owned a home with NG and I purposely chose a simple single stage heat pump when it was replaced last year but that's mainly because I invested in expensive HVAC service equipment several years ago and found a local dealer who would sell me parts and R-410A to service my own unit; I did this after being plagued with breakdowns and not finding a local pro to fix the issue. If I had bought a unit with an ECM motor or a two-stage unit I would have knocked myself out of being able to perform my own service, but that's not a reason for most folks to stay away from those more efficient systems.
 
I have a heat pump & am I am on total electric. I also live in the Midwest, growing zone 6B. One downside is that the heat is almost cold. The brand is Goodman, outside of that I don't know much about them.
 
My son in law is on the bleeding edge of all this tech. Total fan of "the green deal" just spent a fortune putting solar panels on the house, spent $70+k on a Tesla (to save $$$), Recently had to do a full HVAC replacement. Even he did not go heat pump. He looked into geothermal, and the like but the cost vs benefit was astronomical. So he decided (as did I) to go very high efficiency gas heat. Similar to my system. Along with very high eff AC unit.
The only way around here heat pumps will work when you're shivering at -25 is geothermal or with backup gas/electric. Also with the outrageous electric rates here in IL that also makes them not attractive.
Not saying they don't work. They do. But, you gotta look at outlay vs savings.
 
TomRc said:
Climate matters. Where you live and the specific equipment you choose will affect performance and cost of operation...sometimes dramatically. I live in Northern NY and have used heat pumps exclusively for 4 years now with both pros and cons to show for it. FWIW - I design HVAC systems for a living and can get as deep into the discussion as you wish. Every locality has what is know as a “design day” temperature that systems are targeted towards. This is the lowest outdoor temperature at which your designed system will be able to maintain the temperature in the home. If you know this, we can go from there. If not, share your city & state and I’ll look it up for us to have a baseline to start from. Any recommendation I might have will be subject to change based on design day conditions.
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Would love a deep dive. I’m very interested in learning about this.

I’m also clueless in this lingo.

Lmk if this helps for data for my specific area:

For heating day specifically:

1675538492146.png
 
LMichaels said:
They do. But, you gotta look at outlay vs savings.
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TCO and cost benefit analysis is my game.

Which SEER rating is considered high efficiency where you live?

Our coldest nights are 30ish. I only use the furnace for 60 days or so a year. Home heating is never pushed above 67/68°. Maybe 4 hours of heat per day used during the winter season, say mid Dec through mid Feb.
 
Interesting, I just got the Consumers Power bill, my NG use was 16.7 Mcf last Feb. billing, we installed a new 2 stage unit and this last one…8.5!!
I can’t speak to heat pumps.
I forget the SEER ratings, sorry. I just made the decision and wrote the check.
 
I grabbed SF from your avatar and checked the design temp...it comes back at 40ºF. FWIW - I wouldn’t get too caught up in SEER. Manufacturers will claim maximum SEER numbers based on optimal pairings / conditions and you’ll drown trying to sort through those muddy waters to get real world data and info. Instead, I’ll cut right to the chase and then we can back up our discussions from there. If it were my money and my system that were being replaced and design temperature for my locality is anything more than 15ºF, I’d be looking at a Bosch Bova IDS 2.0 or an Ecoer branded inverter split air source heat pump system to replace the existing furnace & a/c. The new system would consist of an outdoor condenser unit matched with an indoor air handler and offer the energy saving benefits and quiet operation associated with ductless mini-splits while working in harmony with your existing ductwork. Both will offer near full capacity operation down into single digit temperatures and both offer optional backup electric resistive heat packs for additional peace of mind that you likely will never need at this design temperature. In full disclosure, I have no vested interest in either brand...I only have a history of good results with both. If you wanted to save some money in the short term, you can pair one of these inverter outdoor units with your existing NG furnace for a hybrid system and then replace the furnace with an appropriate air handler at the furnace end of life cycle. Now for the questions....ask away!
 
What if it gets colder than the design temp? For example if design temp is 40F and overnight temp falls to 28F at 4am and stays cold until 8am?

Also curios about the cooling.
 
Brett-EDH said:
TCO and cost benefit analysis is my game.

Which SEER rating is considered high efficiency where you live?

Our coldest nights are 30ish. I only use the furnace for 60 days or so a year. Home heating is never pushed above 67/68°. Maybe 4 hours of heat per day used during the winter season, say mid Dec through mid Feb.
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If I can find it, I’ll pull a link from my desktop on Monday when I get back to the office and share it here for you. It’s a great cost comparator among fuel sources based on cost, usage, and anticipated run time data that you input. It fits totally into my curiosity wheelhouse which is why I likely saved it.

Typical SEER rating for traditional split systems is still only 13 SEER here in the Northeast with 14 SEER minimum mandates on the immediate horizon and 17 SEER being high-efficient. The Bosch Bova 2.0 is rated at 20 SEER. We’re kinda the opposite of your situation with only about 85 days of cooling per year.
 
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I'm following this as well Tom. My HVAC was installed fall of 1997 and I'm certain it will need to be replaced in the near future.
 
DanHoo said:
What if it gets colder than the design temp? For example if design temp is 40F and overnight temp falls to 28F at 4am and stays cold until 8am?

Also curios about the cooling.
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Temps in the house drop because the system can’t keep up. We’re experiencing that here right now in the Northeast. Heating design temp is 1ºF. That means that 99% of the time, temps are going to be 1º or higher. Temps last night reached a low of -16ºF. It’s a tough call. Do you design a house to -16 here? Nope. You’ll wind up with oversized equipment that will overheat and shorten it’s life. My current house was built as a total electric home in 1986, so it came with electric baseboard as the primary heating source so we have no ductwork. When I bought the home, I added 7 heads of ductless splits across 3 outdoor units. They shut down at about -5 since they can’t extract heat at those temps (newer ones do go to -15 or so), so I turned them off and instead turned on our electric baseboards before we went to bed. They were also designed to 1º and could not keep up so temps in the house were in the low 50’s this morning. I shut them off about an hour ago and turned the ductless back on when temps got back to zero. We’re now back to a comfortable 68º.
 
Here’s a link that shows design temps across the country for both heating (99% table) and cooling (1% table) for those who might be interested.

Design temps
 
I will be following this thread as my daughter bought a house built 2 years ago in GA it was a teardown. It was an old neighborhood which did not have NG which kind of shocked me and I figured the costs to run that heat pump since the house is all electric would be high but its not. She has a good size house and for 3 days around Christmas we had the coldest weather in maybe 15 years my hvac said more like 25 years with the wind chill, 9 degrees without the wind chill in the morning did not get much above 20 for a few days. Her bill was 210 I have a bigger house so mine was about 221 with NG but of course all her appliances are electric including the water heater where mine is NG, dual fuel stove and my drier is electric. My electric bill was 170 got a pool so its kind of hard to estimate what that bill is because the pool pump when the weather drops below 32 runs constantly to make sure even though its salt water that it does not freeze we still got a light coat of ice on one section of the pool but that was it.

Both of us run 72 me cause I am old and came from the north so just not used to it anymore and she has a 14 month old. My brother in law who is a builder built his house maybe 12 years ago maybe more he did a heat pump for the first floor and did conventional for the second floor. He hated that Heat Pump from the day he moved in never heated or cooled very well but alot has changed. He is getting ready to build a ranch sold that house and I guess the Heat Pump was having problems and he spent 7k I assume to replace it before he could sell it. I guess the Heat Pump thing turned him off he is going with a conventional system in the ranch.

Tom, I uploaded your chart so here are the readings in my county no clue what they mean.
Georgia Cherokee 91 25 0.6
 
Brian B Atlanta said:
I will be following this thread as my daughter bought a house built 2 years ago in GA it was a teardown. It was an old neighborhood which did not have NG which kind of shocked me and I figured the costs to run that heat pump since the house is all electric would be high but its not. She has a good size house and for 3 days around Christmas we had the coldest weather in maybe 15 years my hvac said more like 25 years with the wind chill, 9 degrees without the wind chill in the morning did not get much above 20 for a few days. Her bill was 210 I have a bigger house so mine was about 221 with NG but of course all her appliances are electric including the water heater where mine is NG, dual fuel stove and my drier is electric. My electric bill was 170 got a pool so its kind of hard to estimate what that bill is because the pool pump when the weather drops below 32 runs constantly to make sure even though its salt water that it does not freeze we still got a light coat of ice on one section of the pool but that was it.

Both of us run 72 me cause I am old and came from the north so just not used to it anymore and she has a 14 month old. My brother in law who is a builder built his house maybe 12 years ago maybe more he did a heat pump for the first floor and did conventional for the second floor. He hated that Heat Pump from the day he moved in never heated or cooled very well but alot has changed. He is getting ready to build a ranch sold that house and I guess the Heat Pump was having problems and he spent 7k I assume to replace it before he could sell it. I guess the Heat Pump thing turned him off he is going with a conventional system in the ranch.

Tom, I uploaded your chart so here are the readings in my county no clue what they mean.
Georgia Cherokee 91 25 0.6
Click to expand...
That puts your heating design temp at a very reasonable 25º which would be a great candidate for an inverter heat pump system.

I guess this is probably a good time to mention that anyone with an older traditional split system heat pump who is not in an extreme Southern US area is probably unhappy, fed up, or otherwise disappointed with it’s ability to make heat as the temperatures drop. This is real and true as these unit just didn’t have the capacity to make heat effectively at lower temperatures and a lot of folks were “oversold” on their abilities and potential energy savings. Inverter systems are infinitely better than these old systems. if you adhere to the 15º design temp guideline I suggested as your crossover point, you are well above the threshold for consideration of these systems and should enjoy energy-savings and comfort throughout the year with them in your home. The optional backup electric strips only extend your peace of mind and help to lower this threshold into colder climates at the expense of energy savings when they are called into service on those extreme cold days below 10ºF.
 
A lot of folks have asked or messaged me about the cooling side of things so I’ll take a moment to address that. My cooling design temp here in Northern NY is 86º. That means that for 1% of the year, our outdoor temperatures are expected to be above 86º. We typically design our residential systems to a desired indoor temp of 70º and often are asked to aim for 68º instead. That means when it’s hotter that 86º outside, our systems are going to run non-stop in an effort to keep our home at 68º or 70º and will not be able to satisfy that cooling call for any extended period of time. We oftentimes “walk” these numbers in our favor by designing to a slightly higher outdoor temperature or oversizing the indoor coil by a half ton on traditional systems to increase dehumidification. In my opinion, if you can justify the additional initial expense, an inverter heat pump is a no-brainer in terms of energy efficiency in warmer climates where cooling requirements are more important or more prevalent than heating needs.
 
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So Tom again just trying to get knowledge not changing what I have so you mention 1% over 86 which I used to live in Cape Cod Falmouth so not sure it even is 1%.

So in GA obviously the AC is more important as basically near the end of Feb early March spring starts to arrive. We got about 5 months you really don't need much of anything.

But last year 2022 we had this much less days in 2021 but basically in 2019 off the map. So do these thing actually work for AC I know you mentioned some additional stuff like oversizing the unit or whatever.
YearRankDays Over 90 °F
20222159
20217028
20204645
2019191
 
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