Air source heat pump for fun tube baseboard?

ericah1111

I live in Maryland (design temp 17) and I live in a decently air sealed 1600 sq ft home with fully finIshed basement. The home was built in the 1960's and has an oil boiler with hydronic fin tube baseboard heaters in each (of the many) rooms in the main floor and basement. There is no ductwork in the house and the summer cooling with window units was actually comfortable and not too expensive. There is no natural gas line in our street.

Our oil boiler is old and I would like to replace it with something energy efficient and preferably not oil... Last year our house was warm over the winter, but we spent $1600 on hearing oil.

I would really like an air to water heat pump, but I am having trouble finding a manufacturer that sells in the USA that would be compatible with my existing fin tube baseboard.

We considered mini splits but the layout of the house would make that difficult to effectively heat and cool all rooms. Same problem with running ductwork- no easy way to do that for the whole house.

Any suggestions on a heat pump that will work with baseboard heaters and be energy efficient, or should I give up and get another oil boiler?

HVACNUT

I've seen a few water to air geothermal heat pumps that were retrofitted to add a hydro loop. But that was for low temp radiant, and used as a 1st stage. 2nd stage warm air, 3rd stage warm air with electric heat.
With a 17 degree design day, I don't think you'd be able to comfortably heat the house.
I would do a heat loss calculation. The existing boiler is probably grossly oversized. There are many efficient Energy Star rated oil fired boilers. Buderus, Trio, Biasi.
With an indirect water heater and outdoor reset, you can save at least 30% on fuel consumption. I've had customers tell me they cut their fuel consumption in half with my Buderus installations.
Then, later, you can add a ductless system, which will save tons over window units.
And they can be used for heat as well during the shoulder months.

Rich_49

You will have no clear idea if any heat pump will work in your specific house until a room by room heat loss is performed and the installed radiation in each room is measured and reconciled against that BTUh requirement to determine if a heat pump can be effective . If you cannot find someone to do this you may ask here , this is something that can be done remotely .

Ironman

As mentioned, the issue is going to be that an air to water heat pump can only produce about 120* water at best. Your base boards were probably designed for 180* SWT.

At 120* SWT, you're BBs would have about 1/4 of their rated output.

Where in MD are you. We may know someone near to recommend.

As HVACNUT mentioned, the oil fired Buderus done properly could easily save 30%+ in fuel. Going with a propane fired mod/con could do the same.

ericah1111

I live in Greenbelt, MD which is in the D.C. Metro area (PG county). Is there anyone around here you recommend?

I just had the current Peerless oil boiler serviced today. It had been neglected for years by the previous owners and the guys we hired last year did not fully clean it out, so it was a lot of labor $$$. They said the boiler itself was fine now, but we will need a new firebox in a year or two.

I suspect that the boiler and system is oversized, since it can get super hot inside. There are also not enough zones.

I would like to get a proper heat load calculation done. I don't have a house plan currently, is there software you recommend to input the info to get it to someone to do the Manual J?

Thanks for the helpful insights!

ericah1111

Not enough zones = there are 3 pipes for the main house that are on one zone, with the thermostat in the basement. We could put more zone valves to put more thermostats where it makes sense based on the current piping.

Ironman

Try Dan Foley at Foley Mechanical in Lorton, VA.

Solid_Fuel_Man

More zones also means smaller heat output at a given time (generally) which can also lead to short-cycleing of equipment. In a residential application pretty much any oil boiler will be way oversized, and many small zoned just adds insult to injury.

Gas (propane in your case) will modulate and are available with much lower outputs so would more efficient.....BUT.....propane may be more expensive than oil in your area. Ask yourlocal fuel suppliers about oil and propane prices. Also ask about owning your own propane tank if that would be a worthwhile investment as well.