Ten years into a tight Tioga house, the air starts to feel used
The newer the house, the more it needs help breathing. Around the decade mark, owners notice.
The decade mark
A family bought in the Town of Tioga when the house was new. Ten years on, the system still cools fine, but the house has developed a character: a closed-up smell on returning from a weekend away, windows that fog on cool mornings, a headache-y stuffiness in the bedrooms by dawn, a bathroom that never quite dries. Nothing is broken. The house was simply built to a standard that assumed a ventilator would be added, and it never was.
The same thing is surfacing in Oakmont, in the newer phases of Haile Plantation, and in the infill homes going up around the Duckpond’s edges. The tighter the construction, the sooner the decade mark arrives.
Why the climate decides the equipment
Gainesville is wet for most of the year. Dew points sit in the upper 60s and low 70s from May into October, and the mild shoulder months of April and November are still humid. A plain fresh-air fan would pump that moisture into the house faster than the air conditioner could remove it. The fix is an energy recovery ventilator, an ERV, which pushes stale air out and pulls fresh air in through a core where the two streams exchange heat and moisture without mixing. In August the outgoing cool, dry air pre-conditions the incoming hot, wet air. On a 28-degree January morning the exchange runs the other way. The heat-only recovery ventilators sold in cold climates do not manage the moisture, and we do not install them here.
Pros and cons
For an ERV: steady fresh air without opening windows into pollen or humidity; lower indoor carbon dioxide and fewer morning headaches; bathroom and cooking moisture carried out continuously; a filtered intake that keeps the oak haze outside; modest energy use because of the recovery core.
Against it: another piece of equipment with a filter and a core to clean; ductwork added to an attic that may already be crowded; modest cost to run; and no help at all with a house that is leaky to begin with, where the fix is sealing, not ventilating.
The alternative, honestly
Opening windows works for about six weeks a year in this town, in the brief dry spells of late October and March, and the March window lands squarely in oak season. Bath fans and a range hood exhaust air but replace it with whatever leaks in, which in a tight house is very little and in a leaky one is hot attic air. A whole-house dehumidifier handles moisture but not stale air. For a tight house, the ERV is the only option that solves the actual problem; for a 1970s ranch, the answer is usually to seal the returns and skip the ventilator entirely. We test the house with a blower door, or use the result from a GRU energy survey, before we recommend either way.
What drives the price
The unit’s capacity, set by the house’s volume and occupant count under the ventilation standard; the duct runs, which are short in a one-story Tioga house with attic access and long in a two-story Oakmont home; where the intake hood can go, since we keep it off the treed side of the lot and away from dryer and water heater vents; whether the system ties into the central return or runs its own dedicated supply; and the filter grade on the intake. Installation is typically a single day. The ERV’s own maintenance, a core wash and a filter change, folds into the spring and fall visits.
Ventilation questions from the newer subdivisions
Why would a house built in 2014 need a ventilator when my 1975 house never did?
Because your 1975 house ventilates itself through every gap in its envelope, at the cost of pulling in humid attic air. A 2014 house in Tioga or Oakmont was built tight enough to pass a blower-door test, and the air inside stays until something moves it. The code answer to that is mechanical ventilation.
Won't bringing in outside air during a Gainesville summer make the house wetter?
With a bare fan, yes. An energy recovery ventilator passes the incoming air across the outgoing air so that heat and a large share of the moisture transfer out before the fresh air reaches the house. That is why we specify ERVs here and not the heat-only HRVs used up north.
Does an ERV help with the pollen in February, or make it worse?
It helps, provided the intake carries a good filter and sits away from the oaks. The alternative, opening windows, brings the pollen straight in. We place the intake hood on the least treed side of the house and check its filter at each maintenance visit.
Can a ventilator be added to a house with a conventional single-speed system?
Yes. The ERV has its own fans and ties into the return duct, so it does not depend on a variable-speed air handler, although it works best when the central blower runs often, which a variable-speed system does.
New house, stale air?
Call and we'll test how tight your house is before recommending a thing.