Conversion from steam heat to mini split heat pump

daveamir

I live in New York City in Brooklyn I have steam heat average 3 bedroom home approximately 2,000 square feet conedison is offering a program where they  install mini splitt heat pumps in the whole house for free some of my neighbors have done it you guys think this is a good idea seems too good to be true to me

Jamie Hall

Brooklyn... you might be able to get by with top end mini-splits and be reasonably comfortable. You won't be as comfortable as you are with steam.

daveamir

Thank you for the response I was wondering the cost Factor I know myself running the AC in the summer cost a pretty good dime curious about anyone's experience running mini splits for the whole winter

EBEBRATT-Ed

@daveamir

Heat pumps claim they can heat in a cold climate. Some say they will and some swear they won't.

The colder it gets outside the less heating output they have and below 32 deg they have to defrost.

If you put them in fine. I would not let anyone disable the steam

Hot_water_fan

If possible, avoid a multi-split (one outdoor unit connected to many indoor units), in favor of one-to-one units (ducted, ductless, whatever). That'll be better matched to the load of your house and lead to higher performance. Defrost isn't a big deal.

As to cost:

$/MMBtu output = marginal $/unit x unit/btus x 1,000,000 / COP is how to compare energy costs. Lower is better. A steam boiler as a COP of about .8 and a minisplit is around 3, but will vary based on outdoor temperature.

It's perfectly okay to keep both systems.

KC_Jones

Will it be free again in 10+/- years when they all start failing and need replaced? How much are they paying for the yearly, or bi yearly cleaning on all those heads? How much cost savings will there really be in the long run? Looks good now, but will it still look good in the long run?

It's short sighted IMHO.

wmgeorge

Wonder how many of the comments come from people who actually own a Mini Split? Mine does a good job 10 degrees and above. In fact it can cook you out. Yes you need to clean the outside unit, we have cottonwood the HVACs guy friend in the summer of course but I have only cleaned mine once in 3 years. The inside coil is a SOB to clean needs to be done once every two years. I pay 8 cents per kWh in the winter, but it heats and cools fine. I am skeptical of anything "free" what is the catch?
Stay away from the multi head mini's they can be a service nightmare.

Jamie Hall

Sort of implied in @wmgeorge 's comment -- so much depends on exactly where you are and the conditions you are working under and energy costs. There is no one right answer.

daveamir

Con Edison will give them away free if they disable your steam heat meaning a plumber will come and disconnect the heating system and you will only be able to use the mini splits as your source of heating and cooling I guess that's the catch a lot of people in my area have been doing it but I'm skeptical just want to know anyone's experience if anyone has it and what the bills are in New York City and I know electric can be pricey a few times my steam system hasn't worked and I've had to use electric heaters my electric bill has been significantly higher that's why I'm a little cautious installers telling me I can go back to steam after 3 years I have to check if he's really telling the truth thank you for the info guys

wmgeorge

You folks out East seem to be stuck with extremely high electric costs? Not sure why and you don't use AC? For you a heat pump might not make sense, and if you do not need AC why would you want to switch?

But it seems natural gas is bad for GWP and for that I say BS. The world weather has been changing warmer - colder for thousands yes even millions of years. Said it before we need to start building the new design nuclear power plants 2 years ago if we are going ALL electric including cars and pickups.

I am using a Mini because I needed to replace on my 4 season porch... a old, old NG furnace and AC and the Mini made sense. Would I replace my wonderful Trane 96% 2 stage ECM motor NG unit, you would need to pry the thermostat out of my cold dead hands!

reggi

daveamir said:

 installers telling me I can go back to steam after 3 years I have to check if he's really telling the truth thank you for the info guys

I would need to see that in whatever contract they have. .. PLUS the fine print could cost you a little fortune to comply with when you want to get warm again..
TBH...JMO.... I couldn't wrap my head around the thought of no gas boiler in the house especially over the past few months..

Make yourself a informed decision that you'll have to live with 

But I guess if you don't like it you can always sell the place and move... the new owners will be obligated to the contract?? Right? Just wondering 

fentonc

I think the level of incentive from ConEdison depends on if you actually decomission your gas boiler or if you just use a thermostat to relegate it to 'emergency heat' (they mention both on their website). An electric heat pump is not the same thing as a resistive electric heater (what you think of as a plug-in 'space heater'), and in the NY climate is probably ~3x more efficient on average (that number is the 'coefficient of performance', or CoP of the heat pump) across the season than a space heater.

NYC has both expensive electricity and expensive gas, and the gas supply is very constrained in the winter (much more so than the electric supply, which is sized to accommodate summer air conditioning demand), so they are trying to transition people over to using heat pumps. Conveniently, they're also very efficient air conditioners in the summer. I'm in ConEd territory north of the city, and on my last bill I paid $0.225/kwh for electricity and $2.32/therm for gas, so a heat pump only needs a CoP of 2.375 to be cheaper to operate than my ~80% efficient gas boiler. I also only have very inefficient portable or through-wall A/C units for cooling in the summer, so I'm strongly considering taking ConEd up on their mini-split offer.

If you're worried about carbon emissions, for NY's grid it probably puts less CO2 into the air to use a heat pump than an 80% efficient boiler down to a CoP of 1.4 or so. NYC's design temperature is only like 12F, so cold climate heat pumps ('hyper heat') can easily keep up at those temps.

Ironman

Old houses that have steam were constructed needing radiant heat, not forced air. Replacing a radiator system with forced air can cause the house to be very uncomfortable in cold weather. Nobody seems to wanna talk about this until after it’s done and they’re always cold - even with the thermostat set at 75*.

EBEBRATT-Ed

@Ironman is right. anything that heats the air but is not periter heat in an older building results in "cold 70 degrees"

And yes, it's an actual thing

daveamir

Thank you guys I think I'll just stick with what works and keep the steam it's not worth dealing with the grief my wife would give me if she was cold and she loves the steam so steam wins 

des16

I live in a 100 year old stone house upstate NY with an old steam boiler that just died. I have 25 2-pipe radiators. I am deciding between replacing the boiler and installing Ultra-low temp ducted mini-splits. The cost of the minisplits is about 50% more. I presume I will likely never make back the money, especially since we are in Utah 3 winter months. But I am inclined to do it, other than concern that the heat will be less comfortable. The HVAC says that I will not see or hear air flow like hot-air systems, which I despise. But I am an concerned nonetheless the heat will not be as comfortable. Any experience welcome in such an installation.

Jamie Hall

Not only will you never make back the money -- which will be more than 50% more, guaranteed -- but you will never be comfortable again in there on colder days. Since "upstate New York" is a very flexible term -- to my way of thinking it's Watertown or Plattsburgh, but to some folks it's Dutchess County -- I can't say whether even ultra low temp mini-splits will work at all or not, but they may not, or may have to switch to electric resistance heat (very expensive to run) on the colder days.

That said there is something to be said to installing mini-splits for the air conditioning, and to provide comfort heat in the shoulder seasons -- fall and spring. That works well. But you should keep the steam if you want to be able to use, never mind be warm in, the house in the winter time.

I might add that installing the units in a stone house would be interesting, to say the least.