Our team recently attended the North American Passive House Conference in Seattle – one of our favorites for learning the latest and greatest in Ultra High Performance Home Construction. One of the principles of a high performance home is air tightness, so today we’re talking about ventilation in our hot, humid climate here in Georgia.
First, let’s look at where we are today. To achieve air tightness in the Under 2 ACH (air changes per hour) range, manual ventilation must be supplied to prevent bad, stale air from building up in a home. The most common way of doing this in Georgia is to add a fresh air vent to the HVAC unit, but when the HVAC unit is not operating, no fresh air is being changed. Also, this method does not really supply an accurate amount of fresh air to the areas that need it the most, and in our climate, just the latent humidity load required for ventilation equates to close to 12,000 BTUs on an average home.
The current trend and best solution we have right now is adding another system to the home. An Ultra–Aire dehumidifier handles both ventilation and dehumidification. Depending on the size of the unit, it’s $4,000 to $5,000 with install.
Looking to the future, all-in-one units are starting to come on the market. One of the newest is the Minotair, a nice, compact unit that almost does it all. The Minotair provides 12,000 BTUs of cooling, 6,000 BTUs of heating, HEPA filtrations and sensors for VOC and CO2 levels. Earlier this year, Eco Custom Homes completed a two-story, 3,000-square-foot home that had a cooling load of 29,000 BTUs. We used a zoned mini-split system and added energy recovery ventilation (ERV). In the not-too-distant future, three Minotair units (one per floor) could be the answer.
As homes become more airtight and efficient, we will continue to see less heating and cooling needed. While the Minotair is a step up from what we have seen in the past few years, it still does not provide enough heating or cooling for our climate. Within the next decade, we believe all-in-one systems will be the norm and the answer we’re looking for here in Georgia.