CEF explains: Mechanical upgrades vs. building envelope

When you first start looking into home energy upgrades, you might come across terms like “mechanical upgrades” or the “building envelope”. What do they mean, and what’s more important to focus on in your home?

What is a building envelope?

The building envelope (as considered by a home energy assessment) is the living space inside your home that is heated by a central or permanently wired system.

What home energy upgrades can improve the building envelope?

Building envelope upgrades are typically upgrades made to the physical building with the goal of reducing heat loss. They may include, but are not limited to:

  • Adding exterior insulation.
  • Insulating the cavities between wall studs.
  • Insulating attics and providing necessary ventilation.
  • Insulating basements and rim joists (for example with closed cell spray foam and a fire-barrier).
  • Air-sealing (reducing heat loss because of air leaks).
  • Replacing windows or doors with Energy Star equivalents.

What are mechanical upgrades?

Mechanical upgrades, as the name suggests, typically involve replacing or adding machinery that is installed to heat, cool and ventilate your home. Some examples include:

  • Furnaces
  • Boilers
  • Heat pumps
  • Heat-recovery ventilators
  • Exhaust fans

How do you know where to start?

It’s often best to make building envelope upgrades first, followed by mechanical upgrades and then upgrades like solar. One of the main reasons for this is it doesn’t make sense to spend significant money on mechanical upgrades for a home with poor insulation, as you won’t be able to maximize the benefits.

It’s also important to consider your return on investment, which the Clean Energy Financing program will do for you. Mechanical upgrades tend to cost more than building envelope upgrades and also have a limited lifetime, whereas many building envelope upgrades can reasonably be expected to last the life of the home. However, if your home is already well insulated, you can get the most out of mechanical upgrades like heat pumps.

How can Clean Energy Financing help?

In the Clean Energy Financing program, a Home Energy Advisor will work with you in a consultation role to determine the best upgrade plan for your home. They’ll take your actual energy use into account to help project potential savings, recommend specific upgrades and review quotes from contractors.

Clean Energy Financing is available in 12 municipalities across Nova Scotia. Find out if yours is one and apply today to get home upgrades that will reduce your energy costs.