What us electric cost/KWH?

Will this room require AC in summer mths?

Ductwork is already installed for bonus room?

I assume boiler and heater coil can be run independently of each other.

Baseboard electric heat is relatively cheap to install and can be expensive to operate but probably cheaper than propane fuel. I see nothing wrong with this strategy. Of course your electric service supply will need to e checked for capacity. Sizing is key for comfort and controlling costs. I would want the strip heat to have at least two KW settings, a high and low.

IMO

How much will extending the hydronic to that room cost? Are heat pumps good for heating in your climate? Why have the heat set to 60 F when the room is not occupied?

Can't help you if you don't reply to questions.

What is your location?

What is electric cost/KWH? What is cost/gal for propane?

Will this room require AC in summer mths?

Ductwork is already installed for bonus room?

I assume boiler and heater coil can be run independently of each other.

Baseboard electric heat is relatively cheap to install and can be expensive to operate but probably cheaper than propane fuel. I see nothing wrong with this strategy. Of course your electric service supply will need to e checked for capacity. Sizing is key for comfort and controlling costs. I would want the strip heat to have at least two KW settings, a high and low.

IMO

Sorry - needed to gather some information.

Location is about 50 miles north of New York City. Putnam County
Cost for KWH today is approx $0.055 plus delivery, fees and taxes etc.

When I first filled the propane tank - 1000 gallons - it was about $2.50/gallon

It will require AC but there is an air handler in the attic and a duct could be run into this space relatively easily. Ductwork is not there yet.

That air handler also has a heating coil for supplementary heat if the radiant in insufficient but it could be used to heat this bonus room as well, although that would impact the overall efficiency of the radiant and boiler (as I understand it). It was intended more to get the house temperature up quickly (this is going to be a second home for about a year until we sell and move from the primary residence and we didn't want to keep the heat above 60 when we're not there.)

I don't understand about running the boiler and heater coil independently - I think the heating coil is running off the boiler - there are pipes from the boiler to the heating coil in the air handler - filled with a glycol mix.

We have 400 amp service. I think my contractor is suggesting baseboard with temperature controls - although I don't know how accurate those thermostats are.
Thanks for taking the time to reply. Please ask more questions if I haven't answered clearly.

OK.

I think this is more a case of operating costs.

If you have AC BTU capacity and want AC for bonus room for summer mths then I would go ahead and add the ductwork to the bonus room, both supply and return runs. Ductwork of course should be properly sized.

You need to give me your all inclusive electric cost/KWH so I can run a fuel comparison. Any idea of boiler's efficiency?

I suspect strictly for heating though, the electric baseboard is probably the most operation cost effective. There again though, you will need to decide about summertime AC.

Too bad your condenser is not a conventional heat pump.

IMO

Boiler is supposed to be extremely efficient. I've heard numbers in the high 90's. It's a Buderus modulating condensing unit - I can't tell you anything else about it. Electricity company says rates change daily and summer is higher than winter. Since we haven't lived in the house yet, the bills are not representative of living conditions, but for example, last Februrary we were billed for 389 KWH at the rate of 0.333 plus all the various charges and fees. The total bill for that month was $59.83. Again, this was during construction with NO heat or hot water and probably no lights either at that time. We had a proposal for a heat pump when we were doing the AC but there were some questions about its use in our climate and it was much more expensive to install. Really, would have loved to go geothermal but that was prohibitively expensive and prohibited by zoning laws. Maybe some day solar... Thanks.

You need a cost analysis for up front costs and operating costs over a decade or two using current fuel rates. Of course, you would like to know future fuel costs, but who would not. Analysis will be complicated by the fact that you need to figure in your usage of that room and that zoning a room in a well-insulated house is not as important as in a poorly-insulated one.

Heat pumps have come a long way in cold-temp performance in a very short time. Educate yourself about that. You might find that a mini split heat pump will handle that room quite nicely without mucking around with your existing systems at all.

I find the idea that it should take 24 hours to raise the temp of a room 5 F with hydronic heat preposterous. Even if the system is on the same zone as other parts of the house that would be hard to do. That is especially true in a well-insulated house. (Heat transfer from room to room will be much faster than through the outside walls and ceilings.)

If on a separate zone, which you clearly want anyway, It can heat up fast. With any heat source, there is compromise between fast warm-up and temperature stability, but you should not run into a significant problem with a well-designed system. Putnam should have plenty of contractors that can work with hydronic. If a contractor told me that hydronic would take 24 hr to raise a room 5 F, I would not believe anything that comes from them that says that the room can not be zoned separately. If for some reason it really can not be a separate zone, you might install a fan-coil from the hydronic system to heat that room. That way it could run on the same thermostat as the rest of the floor, but you could, essentially, shut it off. If the room is hard to warm up in a hurry, you could put a box fan in the doorway for a couple of hours to warm it more quickly (blow cold air out at floor level).

Zoning of hydronic heat is relatively easy compared to forced air. Having a heating coil in the forced-air system as a supplement to the pure hydronic is weird. It suggests that the hydronic system does not have sufficient radiators although the boiler is large enough.

I'm a little over my head here but let me clarify - there are 2 kinds of "hydronic" heat. The primary heat is hydronic radiant in-floor Viega heat panels. The hydronic coil in the air handler was recommended by the HVAC contractor because he doubted that the radiant heat would be sufficient. However, we don't really know if he is correct since he is only familiar with a different brand of radiant system and might just have been trying to get us to buy more from him. But we did it because he alarmed us. If we ran ducts from the air handler into the bonus room for heat and a/c we would want to seal up the supply ducts in the rest of that zone in the winter because the radiant heat thermostat would be affected by that heat in those spaces.

Please tell me more about your thoughts about time to raise the temperature with radiant heat. We've been told to keep the heat at a steady temperature and not touch it. Since this will be a second home for at least a year, and we won't be there full time, we've been told to leave it at 60 degrees all the time. When we are there for more than a day or two we can raise it to a more comfortable setting (65-68) but it will take a few days to get it there. That's what we were told. Is that not correct? That was another reason for the heating coil in the air handler - to get the living spaces warmer quickly until the floor could catch up. As far as installing radiant heat in the floor of the bonus room on a separate zone, it would require different piping, manifolds etc. Something I know nothing about. The system was not designed for expansion in separate zones (as in a sub-zone off the second floor) although I suspect it could be done by someone a little more sophisticated than our plumber. What I was told is that it would cost a few thousand more than including it as part of the current second floor zone NOW. If we don't do that we can add radiant heat at a later time but will have to pump it up as a separate zone from the basement at considerably greater cost. Right now the bonus room floor is unfinished and is directly connected to the second floor. It would be easy to connect the tubing to what's already in the hallway outside it. It's the issue of heating a less-used space unnecessarily that makes this a difficult decision for me.

Thanks again for your views.