An HVAC question for the handymen/women

[jmebonner]

I'm going to install a forced air heater, hopefully before winter. *fingers crossed* Then, when summer comes around, I hope to add a condenser and all that for the a/c.

Never done it, nor seen it done, but I have a few people to ask questions of if I need them. However, you guys know a lot too, so I'll take any tips I can get.

First, I need to know how to calculate the size of heater I'l need. I heard of a calculator you take the cubic feet and then account for windoes, doors, amount of insulation, etc. If anyone knows this formula, please let me know, it would help a bunch.

I'll be using sheet metal for the main run and branching off of it with flex tubing. I've got a mid 30's steam heat system atm, which will all have to come out, asbestos and all. If you need to know anything else to help with the hints, let me know.

Thanks!!!

[pickel]

I have about 1700 sq. ft. heated area and have 7.5 kw heaters. A bit over kill, so I disconnected the third stage and run on about 4.5 comfortably but mostly relie on the wood burning insert in the fireplace.

[nunyadam]

thats a big project to tackle if you have no experience at it. Also I wouldn't say that Asbestos word very loudly. I know In IL you have to be licensed to remove it. (plastic suits respirators. A big mess. I'm assuming you are refferring to the pipe wrap being asbestos.

[surreal]

handy women. Ain't he nice

I can't help with that but if your treadle sewing machine is broke or dirty I can help!
That's my new hobby.

[jmebonner]

pickel- I will rely mostly on the corn burner with the forced air mainly to ezualize the temp upstairs. I'll check out that size of heater...It's for about 2100 sq. ft, so that may be about right for me.

Nunya- pffft, I scoff at the word 'experience' LOL. Everything I've done so far on both my houses has been without experience. I will wet the asbestos wrap thoroughly to eliminate any dust that would be generated.

Surreal, thanks for the offer on the sewing machine. I assume that you did find that bobbin you so desperately searched for a few months ago?

[surreal]

Actually I didn't that's why I now own 3 treadles.. (well it made sense to me,, if you get it explain it to Fingers for me)

[jmebonner]

Bump...anyone know of a calculator for determining the btu's needed?

[Chuckiechan]

Why not just call a heating and cooling company and ask them? I don't think they will lie to you!

If you have a two story house, condider a "split system".

[pickel]

http://www.hearth.com/calc/btucalc.html

[TOAD6147]

Sounds like about 40,000 BTU nominal capacity which equals approximately 42,200 kW . Are you talking electric heat or gas? Putting in the heater/air handler I'm sure you won't have a problem with if you already have the prper duct system. But when it comes time to hook up that A/C it's a whole different story. You will definitely need a professional when the time comes.

[jmebonner]

Thanks Chuckie, pickel and TOAD!

Toad, yeah that's the plan. I plan to put the ductwork and the heater in pretty soon. I know a guy who lives about a block behind me that ran a lennox heating and cooling business. I imagine I'll have him help me with the a/c.

The calculator sais 33000 minimum and 66,000 max, but that's for 8" ceilings, mine are 9, so I'll add a few thousand more btus I guess .

[TOAD6147]

The calculator sais 33000 minimum and 66,000 max, but that's for 8" ceilings, mine are 9, so I'll add a few thousand more BTU I guess

Based on the calculator, the average or median BTU/cu. ft. is 18-20. So, based on your situation that would be 2100 / 8 X 9 X 20 = 47,250, still within the 40,000 BTU nominal range or a 5Kw heat strip. The next nominal gas heater is about 55-60,000 BTU or 8 kW electric so either way you'd be fine. It just depends on how fast you want it to heat you up.

[Omardeth]

well my advice is don't do it yourself unless you really know what your doing . it isn't worth the hassle . if you don't do the ducting right you heater will work to hard to move the air . if you set the ducting up wrong it will take to long to heat your house and use more energy than needed . it is best to pay someone to do it all . if it isn't done right you can make them fix it . if YOu do it wrong your stuck . it sucks but it is something to keep in mind . if you do plan on doing the ducting yourself my advice , other than not doing it , is to set up the ducting so you can damper it . meaning you can have the ac come out of the ceiling and the heat come out close to the floor . with the system set up this way it will heat and cool much faster . also i would set it up in zones so if you are useing a firebox on the bottom floor you can only send heat to the top floor .

[RedFury]

Here's something to consider also, when choosing your furnace...If you plan on adding onto the house later, get the bigger furnace. Otherwise, get the furnace somewhere in the middle range because you will use less energy if you have the furnace run for a while, then off for a while in longer periods of running than a powerful furnace that runs for a couple of minutes and then shuts off. You'll use more energy ramping the furnace up and down than you will heating the house. Similar to highway miles and in town miles. Works on a similar principle.

Omardeths got it right about setting up the flues though, it'll save you headaches down the road, plus you can always get it set up for zone heat with automatic dampers if you install them now.

[Heavy_Equipment]

Duct work has to be properly sized through the entire run, or rooms at the end of the system won't get adequate airflow, and so the system doesn't make excessive noise.
You don't want either of those scenarios.

I would recommend that you have someone with experience do your layout work, like your Lennox buddy. It's a small price to pay for getting it right, and you can still do all of the install yourself.

[jmebonner]

Probably a good idea HE. I'll ask him about doing that. He'll probably have some other tips and hints too.