Help choosing a combi boiler please

Peacebubbles

Hello, 

I am a new homeowner, bought a home in the bare bones stage of renovation. The house is a 620 sq ft 1920s cottage about 100 miles north of NYC in NY. 

I am installing ~450 ft of radiant floors using quik trak over the existing floor in 3 roughly 150ft loops. It will be a 3 loop manifold with single zone closed loop glycol mix heating using 5/16 pex.  

I am trying to work with a plumber/HVAC guy but the available companies are extremely expensive and the reputable smaller guys are extremely busy and I’m trying to keep plugging away at it while I wait for some pro help… trying to get this all done asap so I can get my tile work done in the next month before it gets too cold …   

Finally to the point, I’d like to order my propane combi boiler but I’m having a hard time getting any response or advice as to what size I need.. my calculations give me that I need a roughly 32,000 BTu supply but also I plan to use a glycol mix would reduce my btu by like 30% so I’m thinking I’ll need a roughly 100k BTU unit for my small single occupant house?I don’t see many coming in much less than that anyways…  

Combi boiler would also supply 1 bathroom, kitchen sink and clothes washer with hot water, there’s no reason to have any of those running more than 1 at a time … 

thanks for any feedback, good, bad or indifferent 

Lisa 

ps also wanted to add that I plan to also install a mini split unit as back up so the house won’t be entirely dependent on the radiant floors to keep it at like 75° hopefully… 

Mad Dog_2

Hi Lisa! Congratulations on the home.  I consult in your area most weekends and can determine EXACTLY what size combo unit you'll need.  There are several Very Good units out there.  Pretty much all the boiler & water heater manufacturers have a good combination model: Navien, Laars, Rinnai, et al.  
I can review your whole plumbing,  heating and cooling system and building envelope and make sure you're getting the best investment dollars 💵 out of your projects. Here to help!   Our ad is linked below.  Matt Mad Dog Sweeney 🐕 

Mad Dog_2

Was up in Red Hook two weekends ago helping out a good friend with his new well pump and tank, domestic hot water.  My daughter is in School in Poughkeepsie...I'm up there all the time....Great area.. Mad Dog 

Mad Dog_2

Jamie Hall

And Lisa -- @Peacebubbles -- @Mad Dog_2 is a good honest man who does top quality work.

hot_rod

Wide of you to find a knowledgable expert to help. Your load number sounds a bit off if you are indicating 32,000 btu/hr for 620 sq ft

Get the Dog down there for a site visit!🐶

Mad Dog_2

Aww shucks Jamie...tanks
Mad Dog 🐕 

seized123

I’m just a homeowner and can’t add anything significant, but here’s a bit of commiseration. I live in the same general area and just lost my sole proprietor plumber of 30 years to retirement. He was awesome, maybe not 100% up to date on the latest heating stuff and codes, but very competent and best of all communication was excellent. For any job there would be an ongoing conversation.

Now I’m shopping around, tried another old time plumber but he’s swamped (skilled labor shortage), I didn’t like the vibe from the bigger company with the nice trucks, now I’m trying out the oil company hoping I like them enough to get a service contract. So far so good with that, though they haven’t done any work yet, but with them I have to first talk to the lady who answers the phone (very nice and experienced), then a tech comes out to evaluate, but he is not going to be the one doing the work, then I try to communicate with the supervisor via email through the lady and don’t hear back yet … we’ll see how it works out. Way of the world now.

Hope you find somebody. Using Mad Dog would be a good idea, lot of experience there and since he’s only consulting he’d be impartial. (We might go that way too but first we need to figure out the big picture like how long we’ll be in this house.)

Good luck. At least you have this forum which is awesome.

GroundUp

I think there may be a little bit of confusion here. There is a very slim chance that you'd be able to push even 10,000 BTU through 450 LF of Quik-Trak, much less 32,000 BTU. That's too little for any combi boiler without some sort of buffer tank. Hopefully Mad Dog can get you squared away