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half-dozen Ways to Ventilate Your Home (and Which is Best)

How a green dwelling house really "breathes."

Should a light-green home require a piece of ventilation equipment like our Zehnder HRV?
Photo: Alex Wilson

One of the features in our new house that I'thou most excited about barely raises an eyebrow with some of our visitors: the ventilation system. I believe we have the highest-efficiency heat-recovery ventilator (HRV) on the market place—or at least information technology's right upwards there near the top.

Why ventilate?

For centuries homes weren't ventilated, and they did all right, didn't they? Why do we need to go to all this try (and often considerable expense) to ventilate houses today?

There are several reasons that ventilation is more important today than it was long agone. Most importantly, houses 100 years ago were really leaky. Ordinarily they didn't have insulation in the walls, then fresh air could pretty easily enter through all the gaps, cracks, and holes in the building envelope.

Also, the building materials used 100 years ago were mostly natural products that didn't result in significant offgassing of volatile organic compounds (VOCs), formaldehyde, flame retardants, and other chemicals that are then prevalent in today's edifice materials, furnishings, and belongings.

Ventilation options

Ventilation can have many unlike forms. Very more often than not, systems can be categorized into almost a half-dozen generic types:

A ventilation organization schematic from the Building Scientific discipline Corporation fact sheet on balanced ventilation.
Image: Building Science Corp.

No ventilation. This is almost certainly the most common option in American homes. At that place is no mechanical system to remove stale indoor air (and moisture) or bring in fresh exterior air. In the distant by, when buildings weren't insulated, this strategy worked reasonably well—relying on the natural leakiness of the house. Information technology's worth noting, though, that fifty-fifty a leaky house doesn't ensure good ventilation. For this strategy to piece of work in that location has to exist either a breeze outside or a significant difference in temperature betwixt outdoor and indoors. Either of these conditions creates a pressure difference between indoors and out, driving that ventilation. On at-home days in the spring and summer, there might be very lilliputian air substitution even in a really leaky house.
Natural ventilation. In this rather uncommon strategy, specific pattern features are incorporated to bring in fresh air and go rid of stale air. Ane approach is to create a solar chimney in which air is heated past the dominicus, becomes more than buoyant, and rises up and out through vents nigh the peak of the building; this lowers the pressure in the business firm, which draws fresh air in through particularly placed inlet ports. The rest of this blog post will focus on mechanical ventilation.
Exhaust-only mechanical ventilation. This is a relatively common strategy in which small exhaust fans, normally in bathrooms, operate either continuously or intermittently to exhaust stale air and moisture generated in those rooms. This strategy creates a modest negative pressure in the business firm, and that pulls in fresh air either through cracks and other air-leakage sites or through strategically placed intentional make-up air inlets. An reward of this strategy is simplicity and low toll. A disadvantage is that the negative pressure can pull in radon and other soil gases that nosotros don't want in houses.
Supply-only ventilation. Every bit the name implies, a fan brings in fresh air, and stale air escapes through cracks and air-leakage sites in the house. The air supply may be delivered to 1 location, dispersed through ducts, or supplied to the ducted distribution arrangement of a forced-air heating organization for dispersal. A supply-only ventilation system pressurizes a house, which can exist a good thing in keeping radon and other contaminants from inbound the house, but it risks forcing moisture-laden air into wall and ceiling cavities where condensation and moisture bug can occur.
Balanced ventilation. Much amend ventilation is provided through a balanced organization in which separate fans drive both inlet and exhaust airflow. This allows us to control where the fresh air comes from, where that fresh air is delivered, and from where frazzle air is drawn. Balanced ventilation systems tin exist either indicate-source or ducted. With ducted systems, it makes sense to deliver fresh air to spaces that are most lived in (living room, bedrooms, etc.) and frazzle indoor air from places where moisture or pollutants are generated (bathrooms, kitchen, hobby room).
Balanced ventilation with estrus recovery. If there are separate fans to introduce fresh air and exhaust indoor air, it makes a lot of sense to locate these fans together and include an air-to-air heat exchanger and then that the outgoing firm air will precondition the incoming outdoor air. This air-to-air heat exchanger—more than commonly referred to today as a heat-recovery ventilator or HRV—is the mode to get in colder climates. A slightly different version, known as an energy-recovery ventilator (ERV), doesn't transfer moisture (oft an advantage when a business firm would get as well dry in the winter or besides humid in the summer).

I'thousand a firm believer that all homes should have mechanical ventilation. With meliorate-insulated, tighter homes, that ventilation is all the more of import. Only even in a very leaky house, one tin't count on bringing in much fresh air or calm days in the bound and autumn when there isn't a pressure level differential across the building envelope.

If budgets allow, going with balanced ventilation is strongly recommended, and if yous're doing that in a relatively cold climate, similar ours, then providing rut recovery is a no-brainer. Mechanical ventilation always takes energy; with heat recovery the energy penalisation of fresh air is minimized.

Alex is founder of BuildingGreen, Inc. In 2012 he founded the Resilient Blueprint Found.

Published Feb 5, 2014 Permalink Commendation

(2014, February 5). six Means to Ventilate Your Home (and Which is All-time). Retrieved from https://world wide web.buildinggreen.com/blog/six-means-ventilate-your-home-and-which-best