Radiator operating temperature 160 vs. 170
2 heating contractors have provided me with proper rad replacements. I currently have cast iron rads and wanted the stelrads.
One of them sized the rads at 160FWT while the other sized the rads at 170FWT.
The ones sized at 170fwt provides me with smaller sized rads since the output btu/h is higher.
However I am wondering what are the disadvantages or advantages of running 160 vs 170fwt.
Low boiler stand by loss. Means uses less fuel, saves money.
So going withe design at 160F is the better choice for savings. Thanx.
And if you decide to have an outdoor reset installed sometime down the road.
It allows you to save more yet with the 160 rads.
I see, yup I was actually reading up on that the other day.
So just for math sakes, what would my current cast Iron Rads be running at ? 140F ?
Depends on how they were sized.
It could be any where from 150 to 180.
I see, no real way for me to tell is there? I tried working out the sqf edr and most of them have 2.75. I then multiplied that by the number of sections which gave me total sqf. However I have no idea what I am suppose to multiply it by after.. I read anywhere from 140 to 170..
Originally Posted by beenthere
I was hoping you perhaps could give you opinion on another matter. My first floor ( open concept) of the house is 43'x 15' with 8' foot ceilings. The contractor that designed at 160F calculated about 23000 btu for that whole floor. I personally found this to be too much, I have 3 double glazed windows, and I have double brick walls with lath/plaster on the inside.House is semi detached.
Do you find that a little too high? I tried various sites for different calculators and it seems they all give different results but never has it been that high..
Your opinion please.
Your cast iron rads would be 150 BTU per sq ft.
I thought you were asking what temp the boiler might be set at. Sorry.
Depends on your wall insulation, and infiltration, not to mention weather or not your floor is insulated over a conditioned basement, or unconditioned basement.
It does sound a bit high.
But, I can't see your place from here.
I would expect 12,500 to 18,000 BTUs in my area.
Yeah i too thought it was a tad bid high. Wall insulation I would say with the double walls and lathe/plaster i am probably getting an R2 value. The attic is going to be re insulated to R40 or R50. The basement is insulated and conditioned, ( home theater room). With living in Toronto, Ontario it gets rather cold here in the winters. Anywhere from -10 to -20 in peak winter months.
Originally Posted by beenthere
One contractor worked it out to about 17500 btus and the other to 23000. Big difference hence why I ask.
Thanx again for your expertise.
Your area is a bit colder then mind. So I'd make a WAG 18,000 to 20,000 is possible.
My current cast iron rads btu output math:
based on the math of 150 BTU you suggested my current rads on the first floor are outputting 25762 BTU/h.
Wow, even more confused now.
can't say about your area.
But around here its common to find cast iron rads 20 to 50% bigger then needed.
More, if it was originally a gravity system.