Sources of Radiant Heat.

When planning for a hydronic heating system, we need to calculate the maximum required water temperature that will be needed to heat the home on the coldest night of the year. Depending on the heat retention of the floor, and the heat load of the building itself, required water temperatures can vary from a low of 85 degrees to a high of 180 degrees. A well designed system operates at the lowest possible temperature, as lower temperature generally means higher efficiency. A mix of temperatures can be supplied if the project requires more than one temperature. This might occur in a building where some of the heating is provided by a radiant floor system that only needs 100 degree water, while the remainder of the heating is met with wall mounted radiators that require 160 degree water. Types of boilers include:

Propane Boilers

A boiler powered by Natural Gas or LP fuel is the most common and versatile hot water generator for hydronic heating. A modulating, condensing boiler can perform at 95% efficiency, making it a good solution for green building projects.

Electric Boilers

When gas isn’t available or practical, electric boilers can be an excellent choice for radiant heating systems. Electric boilers are less to install, and require less maintenance, but can cost more to operate, depending upon the heat source it’s being compared to.

Oil Boilers

While Alternative Energy Systems does not generally install new oil fired boilers due to their higher maintenance costs, we do provide service for all types of existing oil boilers.


When it comes to low operational costs, a Geo-Thermal heat pump will be hard to beat. While the installation cost of a Geo-Thermal heat pump is high, the rewards will more than offset the initial cost (although the payback may take as long as ten years). Alternative Energy Systems is happy to discuss the merits of Geo-Thermal and explain how it can provide a complete heating and cooling system for your home. Although we do not install Geo-Thermal heat pumps, we will partner with a qualified Geo-Thermal installer and connect the heat pump to your radiant floor heating system.

Daikin Altherma

The Daikin Altherma air-to-water ambient heat pump is a good second choice for earth-friendly heat pump technology. Unlike the Geo-Thermal heat pump which requires extensive trenching for the placement of a ground loop, the Daikin unit works like a normal air-source heat pump, collecting low grade heat from the outside air and boosting it to a useful temperature. You can learn more about the Daikin Altherma by visiting their website.

Water Heaters

It’s not unheard of to use a conventional water heater as the source for hot water. The main reason to use a conventional water heater is cost—they are cheaper than other hot water generators. Tankless water heaters are especially tempting because they have better thermal efficiency compared to conventional tank-style water heaters, however they are not designed for, and should generally not be used with hydronic radiant heating systems. More often than not, however, conventional water heaters are a poor choice for radiant heat systems. Before purchasing a conventional water heater, it’s important to understand the limitations of the unit and the heating requirements of the building. Talk with our knowledgeable installers. We’ll research your product, explore all the options and help you decide.


Get a Free Estimate

We are happy to perform a site survey and give you a project estimate free of charge.