Hydro air heating advise

[carboneutral]

I would like some advise for a future heating system in a home I’m currently designing. I have no plans drawn up so I can’t do any load calculations but a figure the house will be 3000sf 2 story with the living on the main level and sleeping above. The ceiling height throughout will be 9ft and maybe some vaulted ceilings on 2nd story.

My plan is to run a Hydro air system the following way:
Connect an air source HP to an air handler with a coil running from a 45-gal high efficiency gas (LP) boiler. If feasible I would like a couple 4x10ft solar panels that feed into a 65-gal hot water tank connected to the gas boiler. I live in the Pacific Northwest so I hope there is enough solar energy to help reduce the cost of running the boiler.

I like the idea of radiant heat but not some of its limitations. I would like real hardwood floors throughout most the main living area and tile in the kitchen. I will be using 1-1/8” subfloor so Warmboard would work out great in the kitchen and maybe in the master bath. The rest of the house will be heated air so should I use conventional duct system or something like Unico high velocity small duct.

Any suggestions on this or a better system would be much appreciated. I’m not sure on brands and models. I was thinking a Buderus boiler and I’ve heard Lennox has a good air handler for pairing up with a gas boiler.

My plan is to live in the home for approx. 20 years so I want something that is comfortable and efficient. Right now electricity rates in my area are $0.0836/KW and LP when I last filled was $1.80/gallon.

[Kevin O'Neill]

Solar is very expensive, even with the tax credits. No pay back there at your electric rates.

[ampulman]

Solar is very expensive, even with the tax credits. No pay back there at your electric rates.

I think he was referring to a solar water heater.

Amp

[Kevin O'Neill]

I think he was referring to a solar water heater.

Amp

Yes.

So was I.

I looked at it for our area. Payback is on the order of 20 to 25 years, assuming no maintenance costs. If his utility rates were higher it would make more sense. But my experience with solar is that maintenance costs are high.

[carboneutral]

So I'll skip the solar panels and hot water heater storage tank for it. What size and kind of gas boiler should I go with?

Also what do you think of Warmboard for kitchen and Unico duct system?

[Kevin O'Neill]

[QUOTE=carboneutral;6470102]So I'll skip the solar panels and hot water heater storage tank for it. What size and kind of gas boiler should I go with?

QUOTE]

You need an accurate load calculation to determine that.

Unico is for tight spaces where there is not room for a traditional duct system. I doubt you can get much over 13 SEER rating with it.

I am not familiar with Warmboard. I do know that in mild climates, you will get very large temperature swings inside with radiant floors.

[carboneutral]

Ok so I can't get load calcs right now so I have to wait on size of equipment. I wnat to focus then on the system and how it will operate. Is Hydro air a good option to consider and if so will using something like Unico high velocity small ducts be ideal or go conventional.

Or should I look into a Gas furnace connected to the HP which is standard for my area but builders I have spoke to don't sped much time considering alternative heating systems.

[DeltaT]

Seattle has number of builders/architects and heating companies that have a great deal of experience in designing/building high efficiency home.

Send me a personal message and I can put you in touch with an architect and a hydronic/solar heating company.

[carboneutral]

Would I really get large temperature swings with radiant heat just in the kitchen. I like the idea of tile in the kitchen and I want it to be comfortable on my feet. What if there was also a toekick register to help even the temp.

Does anyone have experience with Warmboard in this type of application?

I think its all that will work out if the rest of the subfloor is 1-1/8".

[skippedover]

Whew. Many issues. Sit down, this could be long. Sorry.

1. A boiler with a 45-gallon capacity is NOT a high efficiency boiler. It may have a high AFUE rating but the sheer volume of water in it will sap energy like crazy. The high effiency gas boilers typically have water volumes of less than 2-gallons. They also have very thin heat exchangers and big gas flames to get the job done.
2. Radiant heat has its limitations. For one, it can take a long time to heat up and along time to cool down. So if you're in an area where the weather is very cold much of the winter, it's a nice solution most of the time. If you're in an area where it's not all that cold most of the winter, then I'd personally not select radiant as my heating medium of choice.
3. I like your dual fuel arrangement with the air-to-air HP. That could help with the temperature swings you'd experience with the radiant floors during moderate weather conditions.
4. Hydro-air is a compromise for those who have radiant heat and want cooling systems too and also need heat in other areas that are not heated by radiant. It's a method of cutting costs for the installation, since the ducts are going in for a cooling system anyway, why not just add a hot water coil?
5. If you're committed to radiant and hydro-air, please make sure you get a variable speed air handler and the appropriate controls so it's not just an on or off 1-stage system.
6. When YOU (not your builder) find the company that's going to actually do the load calcs and the job for you, make sure it's a low static pressure design. Well, that eliminates the high velocity system, doesn't it? Low static pressure reduces noise (high velocity is high static pressure by design), reduces drafts and lowers the energy bills to operate the system.
7. I'd highly recommend that you consider a modulating gas furnace(s), zoned as appropriate with Hybrid Heat capability. Look at it this way. Assuming the heat load calcs are done properly, you get a 2-stage heat pump so that's 2-stages of heat and 2-stages of cool. Nice! Once the capacity of the HP is exceeded, it is turned off and the modulating gas furnace takes over. If properly sized, it will most likely be ready to stay on constantly for an endless heat cycle. So, what I'm saying is that when the OAT drops from 60 to 50 in a matter of minutes, the HP will be first on and the heat will arrive quickly. A radiant floor will take hours. If the OAT continues to drop, 1st stage HP will soon be too small and 2nd stage will energize. These are very long heat cycles. As the OAT drops further, the 2nd stage HP cycle is continuous and as the indoor temp tries to drop, the gas furnace comes on. Since it's modulating, it "sizes" itself to the current demand (determined by an electronic t-stat that tracks up/down TRENDS rather than degrees) and soon is operating continuously. You are now experiencing continuous heat. Thermostat set-point stays perfectly. Add in IAQ items like high quality UVL, EAC and humidifier is needed and you've got the Cadillac system without all the headaches of a boiler feeding radiant and hydro-air and which system is where and....you get the idea.
8. Domestic hot water? One or more (depending on the size of the home) gas fired tankless water heaters is the ticket. No gas used unless there's a hot water demand. Cold water sandwich issues? Get one that has a very small capacity tank in it. No more cold water sandwich and not vast amount of water stored sapping energy from the planet.

Hope you're not asleep yet.

[carboneutral]

Thanks skippedover that was a lot of helpful info.

So a modulating gas furnace with electric air-to-air HP. What brand would you recommend? And what would you recommend for gas fired tankless heaters?

Im a little worried about being so dependent on price of gas since I live in an area with no natural gas!

What should I do about heating a tiled kitchen area and master bath. That was my main reasoning about choosing hydro air system.

Also could you explain the EAC Im not familiar with that, also it installation (time and materials) for HRV expensive, logically they seem to be a good option to add to any system.

[beenthere]

Better to use a conventional system, then a high velocity system. When eve you have the room for conventional duct.

[carboneutral]

beenthere thanks for advice on using conventional duct system. I see a lot of products out there for heating so its good to know how they perform and in what circumstances they should be used.

Could you help me figure out a good setup in a tiled kitchen? Like I mentioned earlier I want tile so radiant seems the best way to go to make it comfortable to walk on. Could I add a toekick register to keep the room an even temp during moderately cold days?