The first of these grades is what I call “ghetto radiant”. This is the use of a traditional hot water tank system to heat the water that is run through the floors. The worst part is that the water going into the floor is brought back to your water tank and then you are free to use it to wash your dishes or take a shower in. Some authorities permit this so long as the heater is used for both domestic and space heating. However, water heaters used for radiant space heating operate in the temperature range where bacteria, such as Legionella, develop. To prevent this, the water heater must be run continuously in the range of 140 degrees Fahrenheit or higher, and the radiant system must be cycled periodically, regardless of the need for heating. This operating temperature then forces the use of scald protection valves on the domestic side and mixing valves on the heating side. As is often the case, trying to make the systems more affordable and simpler actually results in more complications and hazards.
Also, this type of radiant heat often relies on fresh air vents in the windows to bring in cold, un-tempered air by installing a timer on a fan in the utility room. Translation: Bare –bones, but to code, ventilation that will lead to the stalest air you have ever tasted. Most of these systems are only one zone, so balancing the in-floor loops and getting even heat throughout the house is a nightmare. My family and I lived in one of these homes for one year while our house was being built; let me just say I feel sorry for the next tenant! Being a heating expert and not being able to do any upgrades also drove me nuts, but I digress.
The second level is the “tank less two step”. This would be similar to the “ghetto”, but instead of a horribly inefficient standard hot water tank, it will come with a high efficiency on-demand water heater, such as a Rinnai. The installation of the floor loops and ventilation may stay the same, so while you gain some efficiency; this type is really a wolf in sheep’s clothing. Tank less water heaters, such as a Rinnai, were meant for heating domestic hot water, not your house. When they are used in this application, the manufacturer cuts all your warranties in half, which isn’t really a great sign.
The third level can be best described as, well, the “Right Way”. I don’t have anything clever for this one; let’s just say it leads to happiness and satisfaction. What you have here is a high efficiency heat source such as a wall mount boiler (not water heater) or heat pump that heats the water for the radiant system and domestic hot water, however, this is a closed loop application so the water in the system never touches the water you shower in! Almost all of these applications are heavily zoned to give you maximum comfort control in every living space of the home. Domestic water is heated in an indestructible in-direct fired water tank (heat exchanger) and Ventilation is provided through a Heat Recovery or Energy Recovery Ventilator so all fresh air coming into the house is both filtered and then heated by stale air leaving the house.
One of the most important decisions you can make is choosing the heating company that will install your system. We are generally always high when it comes to install compared to most of our competitors, but it is not just dollars. We have the highest paid technicians, the highest level of design credentials, the highest level of customer satisfaction, the largest service department and the best guarantee, your 100% satisfaction!
It is very important that when you are shopping for a home or building one with radiant heating, you ask about these three simple things.
Heat Source - Is it a water tank, on-demand water heater, boiler or heat pump? What efficiency?
Zoning - Single Zone or Multiple Zoning?
Ventilation - Window/Wall Ports or HRV/ERV?