Not all heating systems are created equal. As you shop around, you'll want to compare apples with apples. Here are some questions you'll want to ask for each price quote you get:

Operating Temperature

What is the operating temperature of the system? You'll want this to be as low as possible for best efficiency. Some designers will "stretch" the system by operating it at a higher temperature. The up front cost may be less, but your operating costs will be more. More information on typical temperature ranges for heat sources and emitters is available.

Pump Size

What size pump(s) run the system? You want the smallest pump possible to do the job; they draw less energy and cost less. Some designers will specify a bigger pump to compensate for smaller tubing sizes.

Tubing Size

Go with the largest diameter that will fit your application. We use 3/4" in concrete and under wood floors and 5/8" in pour-overs. Smaller diameter tubing will not give you as much heat, take larger pumps and cost you more in manifolds.

Heat Output

How many Btu's will the system provide? Have the system sized right! Did the designer do a heat loss specifically for your house?

Heat Distribution Fins

Are Aluminum heat distribution fins specified for under-floor systems? While it is possible to get enough heat without them, the system will respond much slower (a major consideration with any hydronic system).