Question

Can a hot water heater be used with the systems used for in-floor heating?

Asked by pam
Berwick, PA

I'm looking to add heat under my existing floor, only on the first floor in basement, between joists...can a hot water heater be used to circulate the hot water instead of using my oil boiler that is very costly??? Hot water heater would run off of city gas already in the house.

Answer

A hot water heater can be used for in-flooring heating.

  • However plumbing codes prohibit using a hot water heater for both domestic hot water and the supply water for an in-floor heating system in the home.
  • To implement this properly you will need to install a dual pump heat exchanger (see Taco pumps) which does not allow blending of the fluid in the in-floor heating system with the water used for domestic use and potable water.

Domestic hot water heaters do work, but can only supply proper water temperatures for small areas. To properly implement this type of system you must first; consider the size of the room which you are heating and second; the recovery time of the hot water heater. Also since you are looking at installing the piping below the subfloor, the system will require more energy (heat) to heat the room since the wood subfloor will act as an insulator.

Keep your options open.

  • Depending on the running cost of two distinct systems, it may be more beneficial to replace your old boiler with a newer higher efficient gas system.
  • Also consider the implementation of a Boiler Mate indirect fired water heater by Amtrol.

The Boiler Mate will allow for quick temperature recovery for the in-floor heating system thus reducing run time and cost of heating a large storage device such as a hot water heater.

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