In Floor Heat On Demand Water Heater

This space heating system is a hydro air system using a rheem tankless water heater seen on the left.

In floor heat on demand water heater.

The relay tells the system when to start up. The box on the floor lower right is an air handler that includes a copper heat exchange coil. This heating system uses the entire finished floor as a giant radiator. Water from the floors runs back into the water heater.

Radiant floor company pioneered the use of on demand tank less water heaters for radiant floor heating nearly 20 years ago when many in the heating industry believed that on demand water heaters would never work for radiant heat we disagreed. Every heating unit that radiant floor. A pump kicks on and water runs from the water heater and into the floors. A good heater will heat the water quickly have minimal standby loss and lose less heat as water is circulated through the tank.

You will need to be aware of the incoming groundwater temperature as cold water will drop the overall water temperature. So i decided to try a 7kw tankless point of use heater and was pleasantly surprised that it heated the cold concrete slab floor to 70 degrees in a reasonable time. The author s radiant distribution system consists of a primary loop with a heat exchanger for domestic hot water and secondary loops for each heating zone. Hot water is pumped through plastic tubing installed beneath the finished floor surface.

Water heaters are good for radiant floor heating because they maintain a low temperature. If you can see the numbers on the gauges in the photo the water going out is about 100 degrees and the water coming back is about 80 degrees. The temperature of radiant heating water should be in the range between 85 f to 125 f. Energy efficiency is measured by the standby loss of a heater the higher the rating the better the energy efficiency.

The result is a very responsive system that can quickly replenish the lost heat in the pipes and therefore quickly heat the floor in case of floor heating application. A tankless water heater will use 30 less energy and have a rating of 0 82 or higher. Water heated by the tankless heater flows directly through the floor tubing while a heat exchanger provides heat for the dhw supply. Dual purpose systems a dual purpose system relies on only one water heater to supply both the hot water requirements for the home and the warm water needed for the radiant floor heat.

You really only need a maximum of 120 f for your floor. The tankless water heater also provides domestic hot water. That temperature is safe and comfortable as well as being efficient. To heat a floor with hot water hot water will flow through the pipes that are found directly below the floor or via electric mats creating radiant heat that warms up the entire floor.

Above the air handler is a smaller box containing the cooling coil.