Heating loss - include unheated basement?

28W

I did a search on previous posts, but did not find consensus. My house has an unheated basement, almost all below grade. Should I include this in my heat loss calculation?



The house has hot water heat



I did calculate transmission heating loss through the floor for the first floor rooms. I assume this heat goes into the basement and then out, so if I calculate transmission heat loss for the basement, isn't that double counting? I could do an infiltration calculation for the basement.

nicholas bonham-carter

What heating system is being used?

For hot water heat, the sizing should be for building heat loss; however for steam, the boiler sizing would be to the radiation (edr).--NBC

Steamhead

My experience FWIW

is that my house heats fine on a firing rate that does not include the calculated basement heat loss.

28W

Hot water heat

Sorry, I left that out earlier. Hot water heat

Mark Eatherton

As with any hydronic question, the only answer is....

IT DEPENDS!



What are your expectations as it pertains to comfort? What will the long term intended use of the basement space be? Storage forever, or possibly a Man Cave in your future.



I too had a basement with no heat in it, and as Frank said, its stayed reasonably warm, but not comfy enough to lounge around in skantily clad conditions. Now that it is conditioned space, it is comfy from floor to ceiling, and wall to wall.



As for loss through the floor, if the space below IS to be conditioned, then no floor loss from above is considered. If it is NOT going to be conditioned, then it MUST be taken into consideration, but not using the normal delta T used between inside and outside.



As for "un heated" basement, if your heating supply and return lines run through that space, then it is partially conditioned by the loss from the pipe.



I had a customer once who had an old cast iron behemoth out in her enclosed garage. She was using the garage as an office. There were no heat emitters in the garage space, just the old dinosaur boiler. We changed it to an efficient boiler, and that space became uncomfortably cool. She kept saying that the new boiler was too small, and that was why her garagoffice was too cold. No convincing this woman that she was wrong. She got a free wall mounted fan coil and associated piping. I learned an expensive lesson from it. Take that into consideration in your space assessment.



ME

Paul48

28W

Aren't you the person with the new mod/con already installed?

28W

Yes

Yes. I am doing heat loss and radiator output calculations to see which boiler temp curve is appropriate. I know, I know . . . the contractor should have done that. He sized the boiler correctly (all three contractors I got bids from spec'd the same one), and he did a great job on installation. So I'm doing the fine tuning.

CMadatMe

What Miracle

Did he use to size it correctly if he didn't do a heat loss? If I was a betting man I'd think the WB1B10-26 was a better fit..



PS.. Where are the pics you were going to post? Love to see the install..

28W

That's what it is

Vitodens 100 WB1B 26.



It is a very small house (1,300 sq ft) , with excellent roof insulation and very good to excellent windows. Wall insulation is fair to good.



I just finished a careful heat loss calculation using the methods and factors from Taco Flo Pro U., and I get 29,843 Btu at a DTD of 63 degrees.