Condensing boilers are rapidly replacing "conventional" designs in central heating systems in Europe and to a lesser extent in the US. In the United Kingdom, for example all new gas central-heating boilers must be high-efficiency condensing boilers. In the US there is a tax rebate for the installation of condensing boilers. Condensing boiler manufacturers claim that up to 98% thermal efficiency can be achieved compared to 70%-80% with a conventional design. Condensing boilers are designed to recover energy normally discharged to the atmosphere through the flue. The water vapour produced by the burning of gas in the boiler condenses back into liquid water - hence the name "condensing boiler".

An energy efficient house with foam insulation, vapor barrier, house wrap, new windows, door seals and caulking is practically air tight. Preventing the loss of indoor air also means we don't get fresh air into the home. Lack of ventilation can cause humidity and contaminates to build up in the house from cooking, heating, painting and other household activities. So called "tight houses" require an air exchanger or dehumidifier. Air-to-Air Heat Exchanger flush out stale air and replacing it with fresh air from the outside without losing the heat (or cooling).

Air-supply and return ducts can be a medium for mold growth or (with insulated ducts) a source of fiber-shedding, both of which can pose significant indoor air quality concerns. Look for products that allow for easy duct cleaning, or protect against mold growth or fiber-shedding.

Radiant floor heating is a hydronic system-that is, it uses hot water to warm the interior of a home. Unlike baseboard or radiant hydronic systems, radiant floor heating utilizes tubing under the floor to carry and disperse the heat. The floor then acts as a heat sink, retaining the heat for much longer period. While there are several installation variations of radiant flooring, the most common method in Montana is to embed the tubing in concrete or "Gypcrete." The major benefit of hydronic systems is more comfortable heating compared to traditional forced air, near silent operation, better indoor air quality, no need for ducts, plus lower heating costs. They can also be esily adapted to work with solar thermal systems.

European style hydronic radiators and towel warmers

Solar powered attic fans are smart alternatives to conventional roof louvers. They operate during the day and collects power from the sun to convert into electricity. In turn, this energy operates a high efficiency motor inside the power vent, so there's no added cost for electricity. Unlike most electric power vents regulated by a thermostat, it works continuously from sunrise to sunset, keeping the attic ventilated all day instead of waiting for the attic to get overheated. There's no need for electrical hook-up or electricity, simplifying the installation process.

You don't use hot water 24 hours a day. But, you're paying to heat water 24 hours a day. With a standard water heater, you heat and reheat the same water even when you're sleeping. Tankless water heaters are a more efficient way to heat water. It heats water quickly and delivers an endless supply of hot water for as long as you need it. With tankless water heaters, you only pay to heat water when you need it and for as long as you want it.

Older wood stoves and traditional open fireplaces are inefficient and emit high levels of particulate matter. We do not recommend them. However, newer technology, EPA certified clean burning stoves, fireplaces, masonry heaters and pellet stoves are energy efficient and emit very small amounts of invisible particulates and are not considered a big threat to the environment or our health. Even the Green Building Council considers EPA certified wood stoves, inserts and fireplaces acceptable for LEEDs certification. The big advantage of new technology, clean burning wood and pellet stoves and fireplaces is that they do not contribute to global warming because their wood heating is "carbon neutral." Small dimension and scrap wood is considered a renewable and sustainable resource.