NY has a significant rebate program (or tax credit) for putting in a heat pump, however to qualify you have to trash your current central fossil fuel way of heating your home.
Heat pumps are simply amazing at their efficiency and can (especially now) dramatically lower heating bills and should be strongly considered however I do question the wisdom of throwing out the furnace.
First the lower that temperatures get the more inefficient heat pumps get. NY is no slouch when it comes to cold temperatures and can challenge even the best of the heat pumps today, and for heat pumps that are not top of the line, or simply a few years old, simply shutting them down at regular lows that can be expected in NY. This will result in lots of these homes going to resistance electric heat and that has me worried. During these cold snaps which is regional, homes heated by heap pumps will require the most power to stay warm. Cold snaps also strain electrical generation and supply. I do think that this is a recipe for potential black outs during these periods, and frozen and burst pipes.
Power failures themselves can also be regional, and caused by weather events. Over the last 2 decades or so I’ve lived through about 4 major power outages that took over a week to restore (2 of the 4 during pipe freezing weather), and many more of greater than 24 hrs.
It just seems to me that incentivizing stressing the grid when the temperatures are the lowest will lead to mass calls for plumbers to repair broken pipes and flooded homes (and thus raise everyone’s homeowner insurance rates). And burst pipes are bad enough, but this will add that everyone will be looking for plumbers at the same time which leads to much higher demand pricing.
So I am questioning the wisdom of throwing out the furnace and think it may be more responsible to society to keep it. When there is a power emergency declared and people are asked to cut back they could switch back to their fossil fuel burner for that time. This seems the more sensible option.
I also tend to feel that heat pumps are in general less reliable, have shorter life spans, and require more repair time to fix what has gone wrong than furnaces/boilers.
Perhaps I am wrong with some or all of this, but I think we may be moving too quickly here in the right direction for our own good.
I think you’re saying that an oil or gas-fired furnace will still run in a blackout, but the oil furnace in my parents’ house will not, as it needs electricity to operate.
I had replaced a propane furnace with a heat pump about five years ago. My reasons had nothing to do with a tax incentive, but rather that I wanted to get rid of my evaporative cooler and install air conditioning, and the furnace replacement was part of that. I live in the desert southwest, but at 4,000 ft elevation, so it’s not uncommon to have night time temperatures on the lower 20s F, and occasionally less than that.
What I installed was a heat pump with a propane fired furnace as the emergency (or auxiliary) heat source. And what I found out is that the heat pump works quite effectively, with the unit heating with the heat pump about 95% of the time and with propane for the balance. It has a smart thermostat that sends a monthly email to me showing these metrics. And I am happy with the drop in propane use, my overall propane consumption dropped by about 70%. I also use propane for cooking and hot water. Some of the drop was in part due to the fact that the new furnace is 96% efficient, vs 80% for the old one, but mostly due to the fact that the heat pump provided most of the heat.
The city I live in recently extended their natural gas utility to my neighborhood, and I did pay to convert from propane to natural gas. The natural gas is cheaper than propane, but the system still works the same (the heat pump is still cheaper than using gas).
Heat pumps have gotten much better at lower temperature by using inverter motors, so don’t write them off without investigating their capabilities.
If the tax incentive allows the use of fossil fuel as an auxiliary heat source (and perhaps it does, as the heat pump will reduce the fossil fuel use significantly) then I suggest going for it, it will probably save you money. If the tax incentive doesn’t allow it, then consider just making the conversion on your own dime when the furnace needs replacing. That way you can get the equipment you want without having to see if the state approves it or not for the incentive.
I would disagree. Modern furnaces have an electronic motherboard that is very expensive to replace. They also have an igniter for the gas, which is a $100 item (if you let the repairman sell it to you). Modern thermostats are ridiculously expensive. What usually goes out on a heat pump is a capacitor, which is not expensive to replace. That was the only problem we had with ours in 12 years of ownership. It was coupled with the gas furnace, which, as noted above, acted as an emergency heat source when the temperature got too low for the heat pump to operate efficiently. We also installed an on-demand tankless water heater, which is far more efficient than the traditional sort. Between energy rebates, tax credits, and reduced energy costs, we likely recouped our outlay.
From a heat source, of course. Heat pumps are either air source or ground source, with air source being more common since it requires less equipment. How do you get heat from 20 degree outside air? By cooling it to 10 degrees. As the outside temperature drops lower and lower, it gets harder to do this, and that’s when you use the auxiliary heat source (in my case natural gas).
A heat pump is essentially a refrigeration cycle (compressing a working fluid and then allowing it to expand to absorb ambient thermal energy) turned inside out. Instead of making the interior of your house cool and dumping the extra heat outside, it is ‘cooling’ the outside air and dumping what would be considered ‘waste heat’ in a refrigerator inside your house. Because it is doing work to amplify the amount of energy put into the system by moving thermal energy from one place to another instead of directly producing heat, it is actually greater than 100% efficiency (compared to just using the input energy for heating). Typically an air-source heat pump can achieved an efficacy of 2 or 3 (multiples of heating versus direct energy conversion), and ground-source heat pumps can have significantly greater efficacy because of the thermal energy stored in water or soil compared to air.
If you were in a region where temperatures get that low you’d install a ground-source heat pump deep enough that the ‘ambient’ temperature was never below 0 °C. The earth, of course, is a great insulator and heat reservoir (as is a pond more than a few feet deep) and is essentially an ‘infinite’ thermal reservoir for a residence-sized building.
I’m more saying that more people using electric heat will be using more electricity at extreme temperatures and thus increasing the risk of a sustained power failure. So by being able to switch to a furnace at such a time will reduce the chance of a blackout and I presume your parents oil furnace will run with power.
I agree with what you have typed, but this is the sticking point, it does not allow fossil fuel aux heat. And I think that is problematic. Even your glowing post on your heat pump depends on a FF backup and it works great. And I do think that’s the way to go, but the state does not.
None on the Hudson that I am aware of, but NY gets quite a bit of power from hydro and pumped hydro from Niagara Falls. It’s a major supplier that reaches much of the state and supplies about 40% of the power as far away as the greater Albany area. NYC area is a different animal and has far less renewables.
Do you have a/c? A heat pump is the same size. heat in winter, cooling in summer. Easy-peasy. It seems that heat pumps are way more expensive in the US, maybe because the demand isn’t high enough to lower prices. I bought one for mom’s house about ten years ago. With installation it was a little more than $1000, and what she saved paid for it in three years. When she moved out last year, it was still chugging along, no repairs…
For everything you need to know about how they work, if they work in cold weather I refer you to this video. It’s quite long, but goes in depth about the issue. And since the maker lives in Chicago, I think he can speak both for hot and cold temps.
You’ll get a gratuitous amount of bad puns for no extra charge. It’s his thing.
We have a natural gas furnace for our water heater and hot water radiator system. In 2021 we installed a minisplit system that cools and heats the primary living spaces and we use it for heat until the outside temps consistently stay below 40 C or so. Then we turn the furnace on. Until then, though, the areas without a condenser (primarily the two bathrooms) can be a bit chilly.
I’ve looked into replacing the furnace with a heat pump, but my initial research suggests that it may be problematic. The output temps of heat pumps are lower than those of furnaces, so it takes longer to heat the house when you start the furnace up. It could also be an issue with the temps of running hot water.
Does anyone have any experience with this kind of conversion?
From a practical standpoint that does seem counterproductive, however I can see a few reasons why they might not allow it.
Someone could use this as a means to get a rebate for a new air conditioner, who wouldn’t use the heat pump functionality in winter, negating the fossil fuel reduction the rebate is intended for.
Generally heat pumps with gas furnaces fall back to the gas furnace at temperatures approaching freezing. This is a way to cheap out a bit on the capacity of the heat pump. In colder climates you’d want a 2-speed compressor because the system would likely be oversized for air conditioning. The ability to run at “low speed” in the summer would provide adequate cooling without blasting freezing cold air and short-cycling that also doesn’t dehumidify well.
Electric strip heaters can be used to boost the heat pump’s output since they’re located after the refrigeration coil (say the heat pump warms the air to 90 degrees and the strip heaters boost it to 120 degrees). Gas furnaces however are almost always in front of the refrigeration coil, so they can’t boost the heat pump, they can only supplant it, which would lead to more gas use.
Building on #3 above, some people seem to prefer the occasional blasts of hot air followed by the system shutting down as you see with a “normal” gas furnace, versus the longer but not as hot cycles of a heat pump, so they may be inclined to bypass the heat pump in favor of the furnace, basically using “emergency heat” all the time. Think about how often you see programmable thermostats set to “permanent hold”. Sigh.
Modern furnaces go through a lengthy startup procedure that makes them less than ideal for tempering the air during the heat pump’s defrost cycle (when the heat pump basically switches back into A/C mode to melt the ice that forms on the outdoor unit). The heat pump can be nearly done defrosting by the time the furnace gets warm, during which time it’s blowing frigid air into your home that it’s trying to heat. Electric strip heaters get warm almost instantly and also turn off basically instantly. This is a solvable problem with smarter controls, but despite the presence of very expensive control boards and circuitry, HVAC controls in the US are about as sophisticated as a switch tripped by twine and duct tape.
So yeah, while I think it’s lame to require you to ditch your gas furnace if you want the rebate, it’s mostly to prevent people from scamming the system on the one hand, or not running the system in a way that would produce the intended results on the other.
