New radiant heat install on old house

mosher883

I am just looking to make sure I am heading in the correct direction. I currently have a forced air natural gas system and I have/am converting my house to radiant baseboard and in floor heat. I feel this will be a long post.

So I currently have a navian combo 130,000 btu boiler installed and using for my domestic water. I have no heating zones hooked up yet. I detached 1900 sqft garage with 6 loops of on floor heat I installed insulation pipe to garage from house to also use this boiler. My garage is very insulated and is currently heated by a 30,000 BTU heater. Since this is going outside and in concrete I will use glycol and I wanted to keep it separate from my house system so I was going to install a heat exchanger with a pump on both sides.

Now onto the house. My first floor is 750sqft plus 400ft of kitchen all open concept. I plan to use baseboard in the 750 and in floor for the 400ft of kitchen. This will be under subfloor with plates. The way the layout is I would like to only have 38-40 ft of baseboard but calculations say 54ft needed. I feel because I have the 400ft of in floor heat and it's all open it will be okay plus basement will be heated.

The second floor is 515sqft 3 bedrooms and a bathroom roughly all same size. I will have 8ft baseboard in each room. There is a master bathroom that is 400sqft(above kitchen and is all new addition) this is already plumbed with 2 loops of on floor heat under subfloor with plates and the reflective insulation with air gap.

Back to the boiler. I have 1-1/4 main and will tee off to all 3/4 (the in floor heat goes to 1/2 pex) and like I said I plan a pump to heat exchange for garage. Then I'm trying to decide I want 1 pump for 1St and 2nd floor baseboard and use zone valves or to give them each there own pump. Then I plan a pump for both kitchen and master in floor heat with a mixing valve and zone valves so I can control them separately.

Leave in cold pa climate can be down in negative digits. House was 90 percent remodeled last year with all spray foam insulation so I would say it's insulated average to above average. Currently the forced air furnace is 100,000 BTUs and it has no issues.

I know this post is long but let me know if I'm in the right direction or any suggestions or if I'm a complete idiot and should call someone who does this for a living. Side note I am a skilled person I do controls for automation and have very good mechanical background I enjoy learning and doing things myself and saving the money lol

Thanks for any input.

hot_rod

What is the total heat load for the home?

1600 sq for the home 1900 garage?

Some thoughts

It would be nice to run a one temperature system

Either high output baseboard or panel rads

This eliminates mixing valves and the boiler efficiency goes up at lower temperatures

Constant circulation for the garage would eliminate the heat exchanger

hot_rod