Suggestion for Hydronic Heat Questionnaire

[KenB]

Over on the flashlight forum, they have a template for flashlight questions that really helps people specify enough information to get meaningful answers to their questions.

Here is my suggestion for information people might want to supply when asking questions about hydronic (radiant) heating.

Floor Heat Questionnaire
(Get better answers by providing the following information when asking your floor heating question)

1. Where in the world do you live?
2. Building type (pole barn, metal/wood siding, attached/detached garage, etc.)
3. Building size (sq ft)?
4. How many floors?
5. 1st floor ceiling height?
6. Insulation (walls, ceiling, floor)?
7. Energy type (electric, nat. gas, propane, other)?
8. Will you want the system to serve as a hot water supply?



Ken

 

[BadgerBoilerMN]

If a heat load is being done, the window number, size and quality.

For general questions:

1. Location
2. Fuel sources available and cost thereof.
3. Retrofit or new construction.
4. Access to sub-floor.
5. Finished flooring.
6. Domestic hot water option.

Great idea Ken.

 

[jkrash]

What's involved in a heat load test?

I just built a 1 story 30 x 40 cabin in Northeastern Mn. stick built with 1/2 log siding, it has R-19 in the walls, R- 60 in the ceilings, half the building has 8' ceilings the other half has a vaulted ceiling, probably 11' at the highest point. Theirs 4 - 30 x 48" windows in the 3 bedrooms, a 36 x 24" , 42 x 30", & 2 - 54 x 36" inch windows in the building, theirs a 6' sliding door and a 36" man door.

I install 4 loops of rehau 1/2 pex in the slab, (each loop approx. 275') Two inches of blue foam under the slab. I'm going to install a thermolec 11 kw mini boiler and a B&G nrf-22 pump, some cheap stainless headers plus the other components to make up a simple single zone hydronic system filled with 50/50 glycol.
I never heard of a heat load test before, I read elsewhere that a general rule of thumb is 1 KW for every 100 sq ft. of floor space, I figured I could get by with the 11kw if I did a good job of insulating. Do you think it will be enough boiler?

 

[KenB]

Some useful links here: http://www.garagejournal.com/forum/showthread.php?t=140533


Ken

 

[BadgerBoilerMN]

No matter what you are trying to heat, you must have a heat load done first. There are no valid (accurate) "rules of thumb" for radiant floors or any other type of heating. If you oversize everything you may get away with this simplistic idea (a whole industry gets away with it) but if you want efficient, comfortable heat you match the boiler to the load, just as you would match a truck to a trailer.

For instance a 50/50 solution of propylene glycol anti-freeze is considered the standard or a "good rule of thumb". But when you talk to the chief chemical engineer at one of the major manufactures, you quickly find out the difference between "burst" and "flow" protection.

No body wants anti-freeze in a radiant floor heating system.

As for heat loads: http://www.badgerboilerservice.com/images/SampleHeatLoadAnalysis.pdf