There is a builder we follow at Tstud™ that builds to this standard every day. 1900 square foot homes are so energy efficient that they are heated and cooled with only a 15,000 btu Minisplit. A solar panel operates the entire home 80% of the time off grid, so no btu’s are being wasted. Century Home Kits intends to help you build to this same level of energy efficiency so that you can do your part in reducing your carbon footprint.

Correctly installed insulation ensures energy efficiency in every part of the building envelope including ground decks, roofs, lofts, walls, and facades. Insulation is as relevant in cold regions as it is in hot ones. In cold/cool regions, insulation keeps a building warm and limits the need for energy for heating, whereas in hot/warm regions the same insulation systems keep the heat out and reduces the excessive need for btu’s for air conditioning.

An exterior wall is well insulated when its thermal resistance (R value) is high, meaning the heat losses through it are small (reduced U value). Insulation is a key component of the wall to achieve a high R value (or a low U value) for the complete wall. The thermal resistance R of the installed insulation products has to be as high as possible. 80% of all of the openings in a house or a building occur in a wall. If we solve for the wall, we can then easily solve for the rest of the structure.

Air leakages need to be reduced as much as possible in order to create efficient, controllable, comfortable, healthy and durable buildings. With more stringent building regulations requiring better energy efficiency, air tightness is an increasingly important issue.

Details that are vital to achieving good air tightness need to be identified at early design stage. The next and equally important step is to ensure these details are carried over into the construction phase. Careful attention must be paid to sealing gaps and ensuring the continuity of the air barrier. It is far simpler to design and build an airtight construction then to carry out remedial measures in a droughty home.

Consequences of air leakages: cold outside air may be drawn into the home through gaps in the walls, ground floor and ceiling (infiltration), resulting in cold draughts. In some cases, infiltration can cool the surfaces of elements in the structure, leading to condensation. Warm air leaking out through gaps in the dwelling’s envelope (exfiltration) is a major cause of heat loss and, consequently, wasted energy.

The same is true in hot arid or humid areas of the south where you are trying to keep your interior space nice and dry and cool. Those gaps and holes need to be plugged to avoid wasting excessive btu’s for air conditioning. This is called controlling your air changes per hour or ACH.

Most existing buildings, even those built recently, are far from being airtight and because of unwanted air infiltration generate huge costs to owners and occupants, in environmental, financial and health terms.

A leaky dwelling will result in higher CO2 emissions. The additional heat loss will mean that a correctly sized heating system may not be able to meet the demand temperature. Draughts and localized cold spots can cause discomfort. In extreme cases, excessive infiltration may make rooms uncomfortably cold during cooler periods. Excessive air leakage can allow damp air to penetrate the building fabric, degrading the structure and reducing the effectiveness of the insulation.

Ventilation is the intended and controlled ingress and egress of air through buildings, delivering fresh air, and exhausting stale air through purpose-built ventilators in combination with the designed heating system and humidity control, and the fabric of the building itself.

If you do not insulate properly and ventilate too little, you can risk warm humid air condensing on cold, poorly insulated surfaces which will create moisture that allows for molds and fungi to grow.

A controlled ventilation strategy will satisfy the fresh air requirements of an airtight building. Air infiltration or opening of the window cannot be considered an acceptable alternative to designed ventilation.