FAQ

 

Q: What is a "building envelope"?
A: Experts know the shell, or outer layer of your home, as a building envelope. This is the boundary that separates the inside from the outside: The walls and ceiling are part of that boundary. Generally speaking, the areas of a building that are intentionally conditoned (heated) should be considered inside the envelope, and the areas that we don't want to condition will be outside.

Q: What is the best way to stop heat loss?
A: Heat loss occurs due to heat flow through poorly insulated walls and attic spaces, as well as warm air exfiltration. The most noticeable heat loss occurs through air infiltration/ exfiltration and can be remedied by air sealing te leaky area. After the leaks have been stopped, insulation can be added where necessary.

Q: What the heck is "air-sealing"?
A: Air-sealing is basically draft-stopping - we want to eliminate any air movement between the conditioned space and the outside. The benefits of doing this are numerous and you may read more about those here: Air Sealing.html . The methods and products we use to acheive greater air tightness in buildings are many, and may include sealing all penetrations to the attic, dense packing walls with cellulose insulation, or sealing the rim joist with 2-part foam. We may need to remove window casings to seal the gap at the rough opening, or even replace a window.

Q: Doesn’t my house already have insulation?
A: Probably, but does it have enough? If your house was built within the last 30 years, it will likely have some insulation. In Vermont, residential energy code requires R-38 (12" fiberglass or cellulose) for attcs in new construction. The Dept of Energy now recommends R-49 (15" fiberglass or cellulose ) in attics, as does Ashton Thermal. There is less flexibility to improve walls that contain existing insulation and usually the best option is to air seal them. Most 2x4 walls can contain no more than R-11 and 2x6 walls can hold R-19. Batt insulation must be properly placed and cover the entire cavity.

Q: What is R-value?
A: Insulation is rated in terms of its thermal resistance, which indicates its resistance to heat flow. The higher the "R-value", the more effective the insulation. R-values of thermal insulation vary depending on the type of material, its thickness and its density. For multi-layered installation, the R-values of the different layers are simply added up. In short, installing more insulation on your building increases the R-value and the resistance to heat flow.

Q: How can you insulate my walls without removing the siding, or interior finished wall?
A: We typically only need to remove one row of siding to access the wall cavities. We carefully remove a row of siding and drill a hole in each stud bay. We insert a tube into these holes and blow cellulose insulation at high density into the bays. This is known as the dense-pack method. Not only does this increase the thermal resistance of the wall, but it creates a better air barrier against unwanted air exchange between inside and out.

Q: Is there such a thing as a house that's too tight?
A: Well, yes and no... Ashton Thermal takes the position that the building's shell, or envelope, should be as tight as it can possibly be. Once the shell is tight, we test to determine the ventilation requirements of the building as per ASHRAE 62.1, and add ventilation as is necessary. Without proper ventilation, indoor air quality suffers due to lack of fresh air and the build-up of humidity (from cooking, plants, breathing, washing, etc.) and indoor pollutants (off-gasing of carpets and furniture, pet dander, cooking odors, etc.). Older buildings used what we call "natural ventilation", meaning they were so leaky that sweaters and blankets were mandatory equipment 8 months out of the year. It is far better to control the amount of ventilation in a building and change the rate of introduced fresh air, and exhaust of stale air as conditions change during the course of a day.

Q: Does making a home tighter lead to more issues with mold?
A: Not necessarily. Mold issues appear when a home has problems with moisture. These problems may be due to water from improper landscaping or plumbing leaks in the crawl space, improper flashings, lack of exterior rain planes behind siding and/or lack of proper ventilation. Homes should have proper ventilation to help prevent issues with mold. The best building practice is to build a home tight and control the home's ventilation using mechanical ventilation such as kitchen, bathroom and whole house fans. Most new homes are tight enough to need mechanical ventilation with make up air to control moisture.

Q: Why do you evaluate my heating system when you are not a heating contractor?
A: We want to be sure that there are no unsafe conditions in your building before we specify work. We are particularilly concerned about carbon monoxide. If any of your heating appliances emits too much CO, we want you to have the situation fixed. This is a safety issue for you and your family, and we feel an important component of the service we provide. Also, since we are hoping to save you money on your heating bills, we thought it would be nice if we could tell you how efficiently your appliances are working.

Q: Are there government incentive programs available to help defer the cost of performance upgrades to my home?
A: Yes. They are annoyingly and unnecessarily complicated. You can read more about that on the Energy Star website.

Q: How much money will I save?
A: It depends on your building and what condition it is starting from. A home with no insulation will save a lot more than the home with some insulation. Some of the upgrades we recommend will make little difference in the heating bill, but make an enormous difference in comfort. Payback, or return on investment for most of the retrofit insulation and air-sealing jobs we do is under 4 years. We can give you a more accurate assessment if you have us visit for an evaluation. Call now, or contact us using this form.

If you have questions you'd like to see answered on this page, please let us know!