Heating & AC

Think Heating & Air Conditioning Early in Your Project!

Depending on what you are going to use your building for will help determine what kind of heating and A/C you are going to use. Fortunately we live in a climate that does to require A/C – only heating. We decided to use radiant floor heating to take care of our heating needs on the first floor. This decision should be made as early in the process as possible. The cost for a radiant heating system large enough to do 2,000 square feet is about $6,000. Half of that cost will be for the high efficiency water heater. If you choose a different way to heat the structure there are many ways to go.

Infrared heaters fueled by natural gas. The cost involved with this system will be plumbing the natural gas pipe to local building codes, laying the PE pipe from your existing gas meter, getting the proper natural gas fittings and a plumber to hook it up. You can do all the black pipe yourself with some planning and care. Talk to your plumbing and mechanical inspector early on so that he/she can help with some of your preliminary decisions concerning how big the pipe needs to be, how many BTUs will be required to heat the place, and how he/she wants to see the job done.

We ran natural gas piping from our existing house meter by digging (by hand) a trench 4' deep and 100' long. We used a company called Keith Specialties in New Jersey for our pipe and fittings and everything came to about $400. Natural gas pipe does not generally need to be 4' deep but we needed our trench to house our waterline also. That pipe needed to be below the freeze line which is about 36” here in North Idaho. So we used the trench for both the water and the gas. When you put in the pipe be sure to include a solid core wire so that others can find the buried pipe if need be. A roll of 10 or 12 gauge wire will do just fine. Lay it on top of the gas piping and wrap it up the pipe to where it connects to the meter and where it goes into the building.

You could use a wood, pellet or coal fired stove for your heating and then your only requirement would be the proper venting and the purchase of your favorite stove. We did a cabin some years ago and the airtight wood stove from Vermont Castings, all the double wall pipe, roof jacks and raised hearth and surround came to around $3,500.

If you go with a heat pump then you have to consider the cost of the heat pump and the duct work that will have to be done. That means you need to have the pipe and all the registers and you will have to figure out whether it will be exposed or hidden in the walls or floor. We did not price this option as we wanted to go with radiant heating as we are barefooted most of the time. We run a Taekwondo studio and so the natural choice for us was to have warm floors.

If you choose radiant heating there are many factors to consider and we'll cover most of them here based on what type of foundation you choose.

Slab-on-grade
When choosing this option you are going to be pouring the concrete over the PEX tubing used for radiant heating. A great company for the do-it-yourself person is Radiantec. They can supply everything you will need for a “ground up” system at a very reasonable price. All of the manifolds for controlling the water flow is assembled at their factory and shipped to you with little work to do when the parts arrive. Before the concrete is poured and before you lay out your re bar you need to make sure to put down a good quality reflective insulation. You will want to both insulate under the slab as well as on the sides as this is where most of your heat loss will occur. Once you get your insulation down you can prop up the re bar on pedestals and tie everything together with wire. Radiantec recommends that you lay out one course of re bar in 4' sections and then lay in the PEX tubing. Then you crisscross over the top with the remaining re bar and tie everything together. Tie the re bar with wire and the PEX with zip ties – be sure to clip off the excess zip tie as you do not want a zip tie end to poke up through the concrete. Once the PEX is run you will connect it to the in-floor water distribution manifolds. These will be poured right into the floor during the concrete pour. Once finished you will have to knock the wood forms out for the manifolds and then you will have manifold wells established in the floor.

BEFORE YOU POUR CONCRETE: Pressure test the PEX tubing and manifolds. It would be a shame to spend all that money only to have a leak and not be able to get at it. Before the concrete is poured you have opportunity to fix any leak. Leave the system pressurized until after the concrete cures. You will have plenty of time before the next phase of the heating system. The only other cost you may incur is to have a plumber come and sweat (solder) the many fitting together. I hate that particular job and my plumber cost $40 per hour and it took him about 3 hours to do the job.

Plan on between $6,000 - $7,500 for this type of heating system.