Heatpump versus Furnace: A realistic cost comparison for folks deciding about heating methods
Heating cost: Heatpump versus Furnace, a realistic comparison for Bay area
I have two separate HVAC system cooling each floor of my home.
Dec 2023 and Dec 2024 are remarkably similar in heating requirement. My top floor furnace (4 ton propane) operated 42 hr 22 min in 2023 and operated 42 hr 27 min in 2024.
With that being the baseline of comparison, I changed my HVAC setup for downstairs and can provide an apple to orange comparison for home owners. This space is about 1000 sqft in the southbay.
2023: 85% efficient 3 ton (36000 BTU) propane furnace. It was oversized. - operated 24 hrs and 9 mins - uses 0.45 gallons of propane per hour, or a total of 10.8 galloon - I paid 3.77 per gallon for propane prebuy in 2024 - total heating cost 40.7 USD if I needed that for 2024.
2024: 2 ton carrier performance heatpump (24000 BTU), 18 seer cooling, 9.8 HSPF2 heating inverter driven - operated 86 hr 48 min - consumed roughly 221 Kwh, or 2.57 kwh per hour - cost to operate, assuming TOU-D or around 45 cents per Kwh, is 100 dollar this month. - however, I have solar under NEM2 and I am at net zero. I paid 16520 post tax credit for 8kw with about 12000 kwh per year of production. The system is warrantied for 20 years. So my total cost of electricity is 16520 for 240 megawatt or 6.8 cents per KwH - Assuming continued net zero, heating cost with heatpump would be 15 dollar this month.
Comfort
2023: I would say an oversized furnace is much more toasty than heatpump and it brings about a rush of heat that’s very comfortable. However my furnace short cycled which means hot and cold and having a massive flame 2 feet away from my living space was jarring.
2024: heatpump is very quiet and comfortable. The temperature is pretty much the same the whole time. It does bring a rush of warmth if the current temperature is low but not as hot as the furnace.
I also no longer have a long standing itching issue due to heatpump preserving moisture rather than drying it out like a furnace.
Summary: I hope this help folks choosing heating for SF bay area. Overall we live in a mild climate. - heatpump is expensive to install and expensive to run. The only situation where heatpump make financial sense is if you are grandfathered into NEM2. I am not super familiar with NEM3 (the only solar deal you can get right now) but even with a 8kw system I still have to pull from the grid with heatpump daily. I can’t imagine you would be benefiting much from solar unless you can bank credit from summer like I do under NEM2. - Furnace is going to make sense from a pure financial prospective for most people. - This comparison is assuming you are running central heat/cooling. If you have minisplit and only heating / cooling part of your home or a room you may do better.
With all this being said, I am upgrading my upstairs 4 ton furnace to a 4 ton furnace + 3 ton AC or heatpump system but I am not sure if I’ll be using my heatpump much upstairs. Unfortunately, due to PGE pricing, trying to be climate conscious is very expensive.
Of note, I don’t have natural gas. Natural gas is going to be even cheaper than propane.