3 ms·

I live in Ohio in a 100 year old home with cast iron radiators and a natural gas boiler and a gas water heater. I’d love to move to electric but it feels like m

I live in Ohio in a 100 year old home with cast iron radiators and a natural gas boiler and a gas water heater. I’d love to move to electric but it feels like my only real option for keeping the cast iron is something like the Daikin Altherma 3 H HT. Does anyone more knowledgeable of this part of the industry know of any reasonable alternatives for electrifying old houses but keeping the radiators?

ErroneousBosh 16d ago
Underfloor heating works best with air source heat pumps, so just switch to that. Then run a wee bit hot water through your cast iron rads for the look of the thing.
- nickpeterson 16d ago
  I take your point, but what you’re describing would have to cost thousands just in putting in underfloor pipes. It will never make financial sense to do it? Or am I misinterpreting your suggestion?
  - jabl 15d ago
    I don't see how installing underfloor heating in an existing house can make economic sense. Additionally in older houses the windows tend to be a bit leaky, so the radiators being under the windows is important to prevent unpleasant cold drafts. Yes, the heat pump will take an efficiency hit for using radiators rather than underfloor heating. I'd say that's just part of the cost of living in an old house.
Aboutplants 16d ago
Don’t forget to include the natural gas utility distribution costs when calculating any potential financial benefit when looking to switch to fully electric. Your not only getting rid of the natural gas Energy costs, but since your in Ohio, I’d wager your actual Distribution costs for your natural gas supply is actually greater than your actual Natural gas energy Supply costs. Reducing to simply one utility distribution cost will help substantially when looking at long term financial viability
- Brian_K_White 16d ago
  Gas is an important redundancy that will be a huge loss to give up. Not merely the 2nd source of energy, but in a totally different form with totally different pros, cons, and failure modes. It's exceedingly useful that you can run all your gas appliances at full power at the same time without needing the ridiculous amount of copper or aluminum it takes to carry the same load in electric form, and do all that while the power is out, because the power is up on poles and the gas pipe is in the ground. Now imagine trying to replace the redundancy by ups or generator. The amount of copper, electronics, and batteries needed to make a ups that can run your furnace or ac and your stove and hot water is just ridiculous. Most people simply won't have it. Wildly impractical luxury. It's kind of ridiculous to require $billion chip fab infrastructure to make heat, and have your stove be this delicate piece of complex electronics and the burners are all these fixed little circles that don't heat pans evenly because it costs more money to make the fancy burners large enough to cover a whole pan. Meanwhile a gas stove is just a couple chunks of dead metal and almost no moving parts and doesn't even need electricity let alone any electronics. That is a huge practicality and robustness win. And heats pans more evenly because the flame does not have this weird artficially sharp 0%/100% border. Even a small simmer burner heats a large pan more evenly because although there is a hotter spot in the center, the flame still spreads out and travels along the pan and up the sides no matter what size it is. It doesn't care what size the pot or pan is, and also doesn't care what the pan is made out of. That is huge. Electronics and heat are not natural together. It's a constant fight to try to prevent heat from killing elctronics. Every day that one of the thousands of electronic parts of an inductive range sittng above a hot oven and below a hot pan doesn't fail is a lucky day. It's not just reliable by default by just being simple. It's not a slam dunk all-upsides trade-off.
  - nickpeterson 16d ago
    I appreciate the argument, but I can’t make my own natural gas. I was considering all electric with a backup wood burner insert in my chimney. I’ll probably end up with vehicle2home as a backup and solar panels, maybe not in that order. Natural gas is extremely good at generating heat, and I completely understand why people prefer it.
  - 16d ago
Brian_K_White 16d ago
Water or steam? No one likes steam these days because it's old and difficult to install correctly or modify later, but steam has some really cool features. First, it doesn't require a pump to circulate. That means both the mechanical reliability of not having the electric motor and rotating water seal, or any moving part at all(1), but also you don't need any electricity. It doesn't even need the usual low voltage circuit for the thermostat and gas valve. These are not common but also not new, there are millivolt systems where the thermostat & gas valve run only on the electricity generated by the thermocouple on the pilot. It means that when ice has taken down all the power lines in a region, and blocked all the roads for repair crews to fix them at the same time, your heat stays fully working. No air blower, no water pump, not even 24v for the thermostat, and not by dint of having a ups which is just more stuff to fail. Same goes for the hot water and the stove but that's more about gas than steam. There is no getting around the huge efficiency of heat pumps of course. It just still kills me that we are accepting it as normal to require TSMC and ASML $billion chip fab infrastructure to make heat. But I guess you could say the same about leds and light so whatever I'm not saying we shouldn't use heat pumps. (1) there is a moving part in the vent that opens and closes on each radiator, but that is a quality of life and longevity thing. If the vent fails to close or seal, the radiator still works, you still have heat, it just makes a hissing noise and consumes more fresh water which corrodes the boiler faster so it may leak in 5-10 years instead of 20-never.
- nickpeterson 16d ago
  Honestly I wish there was a good way to burn wood in an insert to heat the water that goes through my radiators, to offset an electric system. We tend to get a lot of weeks in the 20 or 30’s where a decent air to water system might do fine, but it would be amazing to burn wood for a few days when it sits at 0.
  - jabl 15d ago
    My father has a wood burning boiler connected to the same water circuit that heats the radiators as his air-water heat pump. Originally when the house was built it was a wood-oil combi boiler, later on the oil burner was ripped out and the heat pump installed (at that point there were government grants available for replacing oil heating with heat pumps). It does work well, and when it gets cold in the winter and the efficiency of the heat pump drops, he burns wood. But honestly the system is a jungle of pipes and valves, and the guys who did the heat pump installation were unable to wrap their heads around it. Luckily my father is a handy guy so he was able to do it himself. But I'm thinking if one were to do something like this from scratch, without the history of the existing boiler already being there and installed, I wouldn't bother with it. Just have a few good old school wood stoves with significant thermal mass (masonry heater or whatever you call them in the US) in the house that you can use to provide extra heat when it's cold, and as backup in case there's an electricity outage.
throw0101d 16d ago
> I live in Ohio in a 100 year old home with cast iron radiators and a natural gas boiler and a gas water heater. I’d love to move to electric […] Perhaps look into "air to water" heat pumps.
- petu 16d ago
  Aren't they meant for underfloor heating? Heat pump efficiency drops with delta T increase, but iron radiators need 60-80C supply.
  - throw0101d 15d ago
    > […] but iron radiators need 60-80C [140-175F] supply. * https://www.bryant.com/en/ca/products/heat-pumps/33nm3/ https://www.bryant.com/en/ca/products/heat-pumps/33nm3/ * https://www.arcticheatpumps.com/high-temperature-heat-pump.html https://www.arcticheatpumps.com/high-temperature-heat-pump.h...
quickthrowman 15d ago
A 98% efficient condensing boiler will be cheaper to operate than a heat pump, we have a ridiculous amount of cheap natural gas in the US.
imp0cat 15d ago
Why keep the cast iron radiators? But if you insist, I believe there are high-temp heat pumps available that will make better use of old-style radiators.
jabl 15d ago
My father has a Mitsubishi air-water heat pump, generating hot water for the iron radiators in the house. Uses R32 refrigerant, not CO2 as in this article, but still. While efficiency is reduced by the need to have decently high temperatures in the radiators, it's still decent-ish. IIRC he still gets a COP of around 2-2.5 when it's -15C outside. This is in Europe, might be different on the other side of the pond.
winstonwinston 15d ago
Basically you add more radiators to keep water temperature low or you add a backup heating source such as typical electric water boiler that will be used only during very cold days to increase water temperature when heat pump cannot keep up.

ErroneousBosh 16d ago

Underfloor heating works best with air source heat pumps, so just switch to that. Then run a wee bit hot water through your cast iron rads for the look of the thing.

nickpeterson 16d ago
I take your point, but what you’re describing would have to cost thousands just in putting in underfloor pipes. It will never make financial sense to do it? Or am I misinterpreting your suggestion?
- jabl 15d ago
  I don't see how installing underfloor heating in an existing house can make economic sense. Additionally in older houses the windows tend to be a bit leaky, so the radiators being under the windows is important to prevent unpleasant cold drafts. Yes, the heat pump will take an efficiency hit for using radiators rather than underfloor heating. I'd say that's just part of the cost of living in an old house.

Aboutplants 16d ago

Don’t forget to include the natural gas utility distribution costs when calculating any potential financial benefit when looking to switch to fully electric. Your not only getting rid of the natural gas Energy costs, but since your in Ohio, I’d wager your actual Distribution costs for your natural gas supply is actually greater than your actual Natural gas energy Supply costs. Reducing to simply one utility distribution cost will help substantially when looking at long term financial viability

Brian_K_White 16d ago
Gas is an important redundancy that will be a huge loss to give up. Not merely the 2nd source of energy, but in a totally different form with totally different pros, cons, and failure modes. It's exceedingly useful that you can run all your gas appliances at full power at the same time without needing the ridiculous amount of copper or aluminum it takes to carry the same load in electric form, and do all that while the power is out, because the power is up on poles and the gas pipe is in the ground. Now imagine trying to replace the redundancy by ups or generator. The amount of copper, electronics, and batteries needed to make a ups that can run your furnace or ac and your stove and hot water is just ridiculous. Most people simply won't have it. Wildly impractical luxury. It's kind of ridiculous to require $billion chip fab infrastructure to make heat, and have your stove be this delicate piece of complex electronics and the burners are all these fixed little circles that don't heat pans evenly because it costs more money to make the fancy burners large enough to cover a whole pan. Meanwhile a gas stove is just a couple chunks of dead metal and almost no moving parts and doesn't even need electricity let alone any electronics. That is a huge practicality and robustness win. And heats pans more evenly because the flame does not have this weird artficially sharp 0%/100% border. Even a small simmer burner heats a large pan more evenly because although there is a hotter spot in the center, the flame still spreads out and travels along the pan and up the sides no matter what size it is. It doesn't care what size the pot or pan is, and also doesn't care what the pan is made out of. That is huge. Electronics and heat are not natural together. It's a constant fight to try to prevent heat from killing elctronics. Every day that one of the thousands of electronic parts of an inductive range sittng above a hot oven and below a hot pan doesn't fail is a lucky day. It's not just reliable by default by just being simple. It's not a slam dunk all-upsides trade-off.
- nickpeterson 16d ago
  I appreciate the argument, but I can’t make my own natural gas. I was considering all electric with a backup wood burner insert in my chimney. I’ll probably end up with vehicle2home as a backup and solar panels, maybe not in that order. Natural gas is extremely good at generating heat, and I completely understand why people prefer it.
- 16d ago

Brian_K_White 16d ago

Water or steam? No one likes steam these days because it's old and difficult to install correctly or modify later, but steam has some really cool features. First, it doesn't require a pump to circulate. That means both the mechanical reliability of not having the electric motor and rotating water seal, or any moving part at all(1), but also you don't need any electricity. It doesn't even need the usual low voltage circuit for the thermostat and gas valve. These are not common but also not new, there are millivolt systems where the thermostat & gas valve run only on the electricity generated by the thermocouple on the pilot. It means that when ice has taken down all the power lines in a region, and blocked all the roads for repair crews to fix them at the same time, your heat stays fully working. No air blower, no water pump, not even 24v for the thermostat, and not by dint of having a ups which is just more stuff to fail. Same goes for the hot water and the stove but that's more about gas than steam. There is no getting around the huge efficiency of heat pumps of course. It just still kills me that we are accepting it as normal to require TSMC and ASML $billion chip fab infrastructure to make heat. But I guess you could say the same about leds and light so whatever I'm not saying we shouldn't use heat pumps. (1) there is a moving part in the vent that opens and closes on each radiator, but that is a quality of life and longevity thing. If the vent fails to close or seal, the radiator still works, you still have heat, it just makes a hissing noise and consumes more fresh water which corrodes the boiler faster so it may leak in 5-10 years instead of 20-never.

nickpeterson 16d ago
Honestly I wish there was a good way to burn wood in an insert to heat the water that goes through my radiators, to offset an electric system. We tend to get a lot of weeks in the 20 or 30’s where a decent air to water system might do fine, but it would be amazing to burn wood for a few days when it sits at 0.
- jabl 15d ago
  My father has a wood burning boiler connected to the same water circuit that heats the radiators as his air-water heat pump. Originally when the house was built it was a wood-oil combi boiler, later on the oil burner was ripped out and the heat pump installed (at that point there were government grants available for replacing oil heating with heat pumps). It does work well, and when it gets cold in the winter and the efficiency of the heat pump drops, he burns wood. But honestly the system is a jungle of pipes and valves, and the guys who did the heat pump installation were unable to wrap their heads around it. Luckily my father is a handy guy so he was able to do it himself. But I'm thinking if one were to do something like this from scratch, without the history of the existing boiler already being there and installed, I wouldn't bother with it. Just have a few good old school wood stoves with significant thermal mass (masonry heater or whatever you call them in the US) in the house that you can use to provide extra heat when it's cold, and as backup in case there's an electricity outage.

throw0101d 16d ago

> I live in Ohio in a 100 year old home with cast iron radiators and a natural gas boiler and a gas water heater. I’d love to move to electric […] Perhaps look into "air to water" heat pumps.

petu 16d ago
Aren't they meant for underfloor heating? Heat pump efficiency drops with delta T increase, but iron radiators need 60-80C supply.
- throw0101d 15d ago
  > […] but iron radiators need 60-80C [140-175F] supply. * https://www.bryant.com/en/ca/products/heat-pumps/33nm3/ https://www.bryant.com/en/ca/products/heat-pumps/33nm3/ * https://www.arcticheatpumps.com/high-temperature-heat-pump.html https://www.arcticheatpumps.com/high-temperature-heat-pump.h...

quickthrowman 15d ago

A 98% efficient condensing boiler will be cheaper to operate than a heat pump, we have a ridiculous amount of cheap natural gas in the US.

imp0cat 15d ago

Why keep the cast iron radiators? But if you insist, I believe there are high-temp heat pumps available that will make better use of old-style radiators.

jabl 15d ago

My father has a Mitsubishi air-water heat pump, generating hot water for the iron radiators in the house. Uses R32 refrigerant, not CO2 as in this article, but still. While efficiency is reduced by the need to have decently high temperatures in the radiators, it's still decent-ish. IIRC he still gets a COP of around 2-2.5 when it's -15C outside. This is in Europe, might be different on the other side of the pond.

winstonwinston 15d ago

Basically you add more radiators to keep water temperature low or you add a backup heating source such as typical electric water boiler that will be used only during very cold days to increase water temperature when heat pump cannot keep up.