Tech Tuesday: Build Tight…But We Still Need Fresh Air Right?

Tech Tuesday: Build Tight…But We Still Need Fresh Air Right?

Written by:  Joe Pasma, Premier SIPS Technical Manager, P.E.                                                                         (my two or is it too cents worth)

Everyone is talking about mechanical ventilation of structures.  Why bother?  The old guys say we build too tight today.  They claim structures don’t breath and that is why we have so many problems with today’s construction.  So, what’s the deal?

In my last posting, What’s in an R-Value, I talked about how tightening up a building, reducing air leakage, helps increase the energy efficiency of the house/building.  Tightening up the structure is great when promoting energy efficiency, but we must remember, people still use these buildings and we need fresh air to function properly.  So, from a buildings perspective, if we are going to tighten the building envelope up to increase energy efficiency, we had better plan on doing something for the occupants of these buildings to provide them the fresh air they require to function properly.  The adage from the building scientists is, “Build it Tight and Ventilate it Right”.

Some say you can never build it too tight but you can under ventilate it.  The key here being proper, controlled ventilation.  Building scientists and energy efficient construction advocates have numerous strategies on how to do this.  The important thing is to incorporate this planned, controlled ventilation into the building.  The actual details of the system used on a given building will depend on the climate zone, the type of occupancy, the mechanical system employed and a whole host of other factors.  But the main take away from this posting should be to plan on some sort of mechanical ventilation in any energy efficient building.

For those of you out there looking to make an existing structure more energy efficient, you undoubtedly will be tightening up the structure; don’t over look the fact that you will need to plan on adding mechanical ventilation to your building.  The same laws of physics and building science apply to both newly constructed buildings and older buildings that are remodeled.


  1. Kate 9 years ago

    Thanks for this great post clarifying that ventilation and leakage are different. We work a lot with the Passive House standard and people often ask, “well if we build a house that tight won’t there be a lack of fresh air?” Mechanical ventilation systems are the perfect complement to a tight building envelope – and Energy Recovery Ventilation systems can significantly reduce the energy consumption of ventilating a building. Check out high-performance SeriousWindows – they have killer air infiltration values and integrate perfectly into tight building envelopes;

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