Energy Efficient Home And Your Thermal Boundary

Breaks in the Thermal Boundary

Our homes are involved in a climate struggle 365 days a year. It’s an on-going battle every home fights. The outdoor climate against the indoor climate determines how comfortable we are, how high our power bill becomes and if we’re going to have an energy efficient home.

The larger the battle, especially if the indoor climate is losing, determines how open we are about learning how to have a more energy efficient home.

The conditioned air inside our home makes up the indoor climate. We are the ones, with the help of a good thermostat,  that determine the temperature of the indoor air.

The indoor air is conditioned by:

1. Heating and cooling systems,
2. Exhaust fans,
3. Open windows,
4. Taking showers,
5. Leaving lights on,
6. Buying a new flat screen, etc.

The outdoor air is conditioned by:

1. Mother nature,
2. Sun flares,
3. The gravity of the moon,
4. Changing seasons,
5. Coal fired power plants, home location, etc.

Breaks in the Air Boundary

Some homes contain all conditioned space while others have a combination of conditioned and unconditioned space. Unconditioned space may include attics, crawlspaces, basements, and attached garages.

Some places, such as furnace and utility rooms are warmed by waste heat and are called unintentional conditioned spaces. They act as buffer zones between the indoor climate and outdoor climate zones. They help slow the transfer or loss of heat.

How to be more energy efficient at home is partly determined by how well the thermal boundary is defined. The conditioned space is identified by that space that is surrounded by the two barriers that make up the Thermal boundary.

1. The Air barrier

• The air barrier restricts the flow of air between the conditioned space and the unconditioned space.

2. The Insulation barrier

• The insulation barrier slows the transfer of heat between the conditioned space and the unconditioned space.

How the Thermal Boundary contributes to energy waste:

Completing the Envelope

Breaks in the air barrier and the insulation barrier result in energy waste. The hole the plumber drilled that was never air sealed and the missing insulation in the attic contribute to energy waste and higher energy bills.

The insulation in the attic that separates one area of unconditioned space from another area of unconditioned space is wasting energy. The insulation is simply in the wrong place.

The dog that ruins the back door weatherstripping has, in-effect, damaged the air barrier and is now contributing to energy waste.

It is a poorly defined and inadequate thermal boundary that contributes to energy waste and inefficiency.

The Role of the Energy Auditor:

It is the energy audit, whether by a professional or by the homeowner, that determines the cost-effectiveness of completing or adding to the thermal boundary. It is also the energy audit that confirms the thermal boundary is in the correct location.

Modern homes that have several dormers, bay windows, roof levels, irregular soffits, and knee walls, are likely to have a broken or misplaced thermal barrier.

Where’s the Thermal Boundary

Factors that determine the thermal boundary’s location are:

• The building shells current insulation level.
• The effectiveness of existing air barriers.
• The structure of the home that will allow a continuous and unbroken thermal boundary.
• The determination of what is conditioned and unconditioned space.

The air barrier and the insulation barrier should be close together, even touching in most areas. Air flowing through and around insulation is one of the most common energy wasters, therefore, the two barriers should be joined, together, on the same plane.

The thermal barrier plays a huge role in your homes battle to separate the indoor climate from the outdoor climate. The two components of the thermal barrier, the air barrier and the insulation barrier, need to be located and installed correctly if your home is going to have a fighting chance to win the climate war.

How to have an energy efficient home has more to do with a good thermal barrier than with a new high-efficiency furnace or heat pump. Don’t spend $5,000 on a new heating system until you spend one quarter of that on your homes thermal barrier.

Thanks for stopping by Detect Energy, hope you will come back soon, but I won’t leave the light on for you…