I'm pretty sure that you can still use whatever heat distribution system you want, but it might add more complexity. Long term I want to install high efficiency radiant baseboard and panel rads heated by an air to water heat pump, that can also heat our domestic hot water. We will have to use a couple of wall or ceiling mounted cassettes in order to get the AC working.In the New England there haven’t been a lot of whole house options available. People generally like to change out like for like, especially when the house doesn’t have ducting which is pretty common here. Many people don’t like the big mini split units on their walls. Having more options where people could swap out their hydronic baseboards running on oil with a baseboard from a heat pump would be nice.
I have an oil boiler for the baseboards and am also ducted for AC. If / when my boiler goes I’ll seriously consider a heat pump that can leverage my existing ducting. But my boiler may last another 25 years so that may not be any time soon. May AC breaking down actually might be what pushes me over to be honest.
When I wanted to get an 80 gallon HPWH in 2011, I called three different plumbers. The first refused to take the bid, but would sell me an 80 gallon conventional. The second jawboned me that I was making a huge mistake, that it would break down and give me lukewarm water and I would be so sorry I would call him back in a couple years and tell him he was right (!!). And then the the third said 'Haven't installed any before, but I'll take the job.' It blew a controller board in Year 4 (after a massive power surge), I replaced it myself with a board the co fedexed me and I was back in business. Still aok in year 9.Even today efficiency is viewed as a luxury. You should have seen the look on my contractors face when I said I wanted 80 gallon hp water heater. “Why would do that when you can have two separate 40 gallon units for way cheaper” is what his face was saying. And I asked why I could not get a single 80 gallon and he said they changed the regulations without even thinking twice about why that was the new standard.
Fundamentally getting high enough temps for standard slant fin type radiators is the big sticking point. The standard home heating calculators assume 160 to 180 degree supply water. It takes a lot more baseboard to put out enough heat to heat a house on areal cold day with 100 degree water. It can be done in many rooms but in places like kitchens its tough. Seigenthaler is big fan of radiant walls and ceilings. They respond quicker than underfloor radiant or infloor radiant, supply temps can be 90 F, but it basically only good for new construction unless someone is doing a full gut. Outdoor air to water units can get up to 130F and maybe 140 F so its not a great fit for existing baseboard. The Euro low temp emitters are several hundred dollars per room. I think I was looking at between 4 and 5 K to switch my small house over. Since I heat with 3 to 4 cords a year with a minisplit for shoulder seasons, hard to justify the upgrade. For a new house in my climate I might just make that move with a small wood boiler and hope the big companies come out with air to water units as right now the selection in the US is limited. Daikin sells them offshore but not in the US last time I looked. Lot to be said for 360,000 btus of backup in a 500 gallon tank heated to 180 F with a standby wood boiler with 90 degree emitters compared to 160,000 btus for a 180F to 140F for standard radiators.In the New England there haven’t been a lot of whole house options available. People generally like to change out like for like, especially when the house doesn’t have ducting which is pretty common here. Many people don’t like the big mini split units on their walls. Having more options where people could swap out their hydronic baseboards running on oil with a baseboard from a heat pump would be nice.
I agree Kenny. Electricity does go out, esp in the heavily wooded area I am in. I can run my 120V loads off a 1.5kW inverter hooked up to my Volt... and a tank of gas runs all those for a week. As for backup space heating... that is what I have a woodstove for!They're also freezing in China, not to sound like a tin foil hat wearer here, but I'm leery of switching to all electric energy sources, I do see some benefit with efficiency, especially with some renewable resources out there, but, putting your faith in electric companies with no back up available is asking for issues....