I would like an expert opinion on which product to use for my application. I am looking for a heating source for the office / bathroom / utility room area in my farm shop. The 3 rooms are connected together (door from one to the others-generally open) and the total area covered is 10'x30'. The ceiling height is 8' and the walls are R-19 or better. The large area of the shop is generally not heated and the office area is of a very "tight" construction. I am on an LP system. I am not in this building that much but need a way to keep the pipes from freezing and to provide adequate heat during the days when I am out there. I am in the Omaha, NE area and we do see our share of the cold.

My concerns are that there will be a lack of fresh air in this small, tightly enclosed area and that the moisture given off by a ventless system would be a problem. Are these concerns justified and would I be better off with a direct vent system. The fact that no electricity is needed is great since it's one less thing to worry about if the power fails. What size unit would I need for this application?

Thanks!

Dear TM83,
In my opinion, you can go with a small hydronic system. From your measurments, you would need a small boiler, 550 BTU per hour output, 18 feet of baseboard and set it at 55 degrees when not in use. Forced venting should not be a problem as the venting is directed outside. Incase of a power outage, simply open the one zone valve you will need and the system will circulate by gravity. Make sure the baseboard is placed on the outside walls/ The formula for each room size is as follows. Multiply lgth. X width. for room area. Multiply that total X 3000.
Divide that total by the number of BTU per hour output and that will give you the amount of baseboard needed for each enclosure. Example: If you have a 10X10 room, you have 100 Sq. ft of area. Multiply 100x 3000 and you will get 300,00. Divide that by 550 (BTU per hour output), you will get 545.etc. The first three numbers will give you the amount of baseboard, ie. 6 feet to adequately heat that space. With an R factor of R-19 and good windows, you should have no problem. Note: For every 2 ft. in heighth over 10 feet, add 10%.
Hope I helped.
P.S. I've use hydronic systems for years and for me, there is no other option. However, If you have frequent power outages, go to a direct vent system.
Len

If you notice, the Iceman is either not good at math, or not good at typing. A 10 foot by 30 foot room in his calculations would be 300 square feet multiplied by 3000 equaling a 900,000 btuh input boiler while he calls for a 550 btuh boiler above that.

You can do a heat load estimate for free following Manual J guidelines at:
http://64.226.150.132/hydronic/hea/index.htm

If your ceiling is insulated to R22 and your walls to R19, your building will require a heating appliance less than 12000 btuh.

A hot water system would be most comfortable as it would surround you with warmth at the walls. However, if looking at cost, I suggest two direct vent warm air units, one at each end. A ventless unit would make the moisture content too high and you would collect the moisture at the cold wall exterior, wetting the insulation.

Thanks for the input. You'll have to excuse my ignorance in regards to hot water systems since in this part of the country we use forced air gas systems almost exclusively. I did live in an apartment in college that had a hot water baseboard system and it was a very nice heat although the temp was hard to regulate. I'm sure the systems are much better now since that was a long time ago.

What would a system like this cost and how much maintenance would it require? Cost is one appealing aspect of the direct vent and ventless systems. Even a forced air gas furnace would be relatively inexpensive at well under $1000. I'm just trying to weigh my options here and see what makes the most sense for this application. I also have to keep in mind (and my wife also is reminding me) that this is not my home but a shop where I am not able to spend a lot of time anyway.

This may be a dumb question, but I'll ask it. Is it possible to tie baseboard heaters in with the hot water heater that will be in the utility room. I assume I would need a suitable pump and some sort of thermostatic control. I've been debating the whole water heater issue also so using it as a heat source does have some appeal. Since the hot water may get used for a half hour per week it seems kind of wastefull to try to keep 40 gallons warm the rest of the time. I've looked at the tankless stuff but they are at least $300 over the cost of the conventional heater. This price difference would buy the LP for a lot of years. Any opinions on whether this may work?

Thanks!!

Using a water heater directly to the baseboard is dangerous as baseboard is not meant for city water or well pressures and may burst sending water throughout. Also, it is unhealthy to let drinking water sit inside heating elements for a long time. However, a water heater used exclusively for heating is possible. If you use a standing-pilot water heater, a gravity-flow system would make your heating independent during a power outage.

Use a point-of-use water heater, an electric hot plate, or an elecric tea-pot for a small amount of hot water. A small electric water heater for domestic use is inexpensive.

Mr.K,
If you would read correctly you would see the example I gave was for a 10' x 10' room. Not 10' x 30'. My math is correct. I've been trained by Weil-Mc Clain in hydronic heating. I gave that example to show the formula. Don't get me wrong. Our goal is to help and opinions are good as they result in friendly conflict and better help to solve the problem. LOL
Len

Len, if Weil-McLain taught you to multiply the square feet of a room by 3000 to arrive at the heat requirements of a room, they have done you a great disservice. The old rules of 40 btuh per square feet or 5 btuh per cubic foot left over from the 60's don't work any more because people are installing R19 walls and R30+ ceilings. I know they do not teach that. 100 times 3000 is 300,000 btuh, there is no 10 x 10 room built without wide open holes that has a heat loss that high.

Divide the 300,000 btuh by 550 btuh per linear foot of baseboard and you arrive at 545 feet of baseboard in a room that only has 100 feet of walls. Stacking baseboard five or six levels high will make a mess and won't work well.

This is not to give people a hard time, just to give accurate information.

Mr. K,
That was 6 feet of baseboard for a 10x10 room.
Len

OK, Len, that could have been the answer without the rest of the stuff. We still can't figure how you got 6 feet of baseboard from:

"Multiply lgth. X width. for room area. Multiply that total X 3000....Divide that by 550 (BTU per hour output), you will get 545.etc"

[This message has been edited by HKestenholz (edited December 19, 2001).]

Look at the "545". The 5 being the first number. The 45 being the second. 5 feet of baseboard. The 45 will tell one to go to the next highest number, which is 6 feet. Again that is the basic formula. Area X btu per hour output of the boiler divided by 3000 ( base number). The base number is always the same. I've used this formula for years and when matched against any other they always come out the same. Thats enough. End of disscussion. LOL
Len