Heat loss calc discussion, radiator placement

Gene Davis_3

I'm a retired engineer, and for enjoyment and a little income, do plans and engineering for clients building new houses, or remodeling existing ones.  I like to know as much as I can about the heating system for a project, so I can draw the plans to accommodate it.

The pics show a small vacation house that will be built on a well-insulated crawlspace, in a climate with about 9000 degree days heating. 

I have downloaded Taco's software that permits heat loss calcs, and want to see what we get in the application.

I am not showing skylights in the images, but there are two.  I think I should treat them as windows and specify accordingly, and for the ceilings above, downgrade the insulation factor a little because of the openings.  Does that seem like the right approach for skylights when using software like this for heat loss?

You can pick it out by a close look at the pics, and see that the mainfloor greatroom has a big ceiling vault above, and windows high up in the gable wall.  I believe I should use the 2D Taco floorplan and upsize the windows on floor MAIN to compensate for the extra glass up high.  Does that seem right?

The plan is to heat using a small mod-con boiler in the crawlspace under the stairs, ladder-accessed through the door shown on the main floor.  Panel radiators with TRVs throughout, will provide the heat.

How does one treat that walk-in closet upstairs?  No radiator, but insulate the walls well to the outside, and insulate the between-walls that divide it from adjoining heated space?

With the kitchen not having any outside walls, do we not place any kind of emitter there?

Would it be good to place a small upright emitter on the main floor at the U in the winder staircase?

Alan (California Radiant) Forbes

Radiator System

Hi Gene:



That's a nice house; panel radiators with TRV's are a good choice and will provide a comfortable environment. 



As far as the skylights: yes, treat them like windows.  Downgrading the insulation is playing it conservatively. it makes the radiators larger and there's nothing wrong with that.  You can reduce your water temperature and your mod/con boiler will become more efficient.  In Germany, the government  dictates a maximum water temperature of 160° to increase efficiency.



As far as the greatroom, just make sure the total square footage of windows and doors is represented in the calculation as well as ceiling height, i.e. total volume of the room.



Check with the local jurisdiction as far as putting the boiler under the stairs; some of them are very sensitive about installing a gas fired appliance under an egress.



I've only installed a radiator once in a closet, but it was a huge closet.  More like a dressing room.  It's your call, but I'd leave it unless your clients want it.  Labor + materials + radiator works out to a lot of money.



The kitchen is small and it's always hard to find a place to hang the radiator.  If there is some space, I'm a big advocate of towel warmers.  I'd put it right there under the bar to keep my legs warm.  People worry about burning their knees; it doesn't happen.



And yes, I'd put a radiator on the wall under the winding staircase.  That's an outside wall and it will be cold.  The owners can adjust the TRV down a notch at that location, enough to take the chill off.



All the best,



Alan

Charlie from wmass

as for the closet

Nothing wrong with mixing in a small piece of perimeter baseboard to keep the chill off. size it for a target of around 60 to 65 degrees and I think you will have a happier customer. If this were as far North as I am it would be like a walk in refrigerator in the winter. Please give the boiler guy a bit of room to swing a wrench when placing the boiler. We can shoe horn them in but a bit of room and everything is easier from the install to the up keep. A small emitter in the kitchen would be good as it will be controled by a trv there is no issue with the cooking appliances over heating the space and the emitter wasting the heat. I like seeing small homes. They are a breath of fresh air. Good luck with your project. No chance for a nice steam system? Had to ask.