Foam Insulation…Is it Really That Easy?

Foam insulation provides superior performance over many other insulation options, but how does it affect your HVAC options? If a home is completely insulated with foam insulation, your home is almost completely air tight. A good thing, right? Not always. First, interior mechanical systems need to be compatible with a foamed house. Because your house is drawing very limited amounts of air from the outside, the gas powered furnace and water heater inside your home will attempt to suck every bit of combustible air out of your house. Since you need this air to breath, that can cause a problem.

Properly insulated home attic in Austin

A high efficiency, sealed direct vent furnace, which costs more, or a heat pump, which does not perform as well in extreme cold, will be required. You will also need either a direct vent water heater, which costs more, or an electric hot water heater, which is not as efficient.

You also need to consider air quality. In a very tight home (i.e. a foamed home), the inside air can become “stale”. Because air is not exchanging with the outside, indoor pollutants can build up and make you or your children sick. A make up source of air from the outside needs to be installed; either a direct vent to the outside or preferably an energy recovery ventilator will be needed.

A foamed house will also affect your ability to have a properly functioning fireplace. You will need to either use a direct vent fireplace, which is not always the most aesthetically pleasing look or again a direct vent to the outside that is very close to the fireplace. If you do not provide adequate combustible air, your fireplace can smoke, not light at all, or worst case back draft into the home. Large commercial style vent hoods will also need a fresh air vent. If not, a large hood vent can literally suck every bit of conditioned air out of a house in 15 minutes.

Foam insulation provides superior insulation qualities, and it’s an excellent product to consider when planning your green remodel or custom home, but make sure you plan wisely so that you do not have any unanticipated adverse affects.