Indoor Air Quality, Duct Sealing, and Aeroseal
A tight modern house holds its temperature beautifully and holds everything else too. Dust, humidity, cooking smoke, pet dander, and whatever the crawlspace is doing. Most of what people call an air quality problem turns out to be a ductwork problem.
Start With the Ductwork, Not the Gadget
There is a whole industry built on selling homeowners air purifiers to solve problems that are actually leaks. Before we talk about equipment, we look at what your duct system is doing, because a return duct pulling air out of a dusty crawlspace will beat any filter you buy.
Typical duct systems lose a meaningful share of the air they move through gaps at joints, boots, and plenums. That air does not disappear. Supply leaks dump conditioned air into the attic. Return leaks pull attic and crawlspace air into the house, which is where the dust, the humidity, and sometimes the smell come from.
If one room is always dusty, look at the boot
The connection where a duct meets the register in the floor or ceiling is one of the leakiest points in a typical house. It is also one of the cheapest to seal properly.
Aeroseal
Sealing duct from the inside. The system is pressurized and an aerosolized sealant is introduced into the airstream, where it collects at the edges of leaks and closes them. It reaches joints buried in walls, ceilings, and chases that nobody can get a hand or a brush to.
The part homeowners appreciate most is that it measures. You get a leakage number before, and a leakage number after, so the result is not a matter of taking our word for it.
Manual duct sealing and duct repair
Where duct is accessible, mastic and mechanical fasteners are still the right answer. Cloth duct tape is not, and if the previous installer used it you will find it hanging off in strips. We also repair crushed flex, disconnected runs, and undersized returns, which are the three things most likely to make one room unusable in summer.
Duct cleaning
Useful in specific situations: after construction or a remodel, after a rodent problem, or when there is visible contamination. It is not an annual ritual, and we will not sell it as one. If somebody quotes you a duct cleaning every year, that is a subscription, not a service.
Air Quality Equipment That Earns Its Keep
Media filtration
A four or five inch media cabinet catches far more than a one inch filter and does it without choking airflow. The cheapest real upgrade in this category.
Whole-house dehumidification
The one that matters most in Delaware. Our summers are humid enough that a correctly sized AC still leaves basements and first floors clammy in shoulder season.
Humidification
The winter opposite. Cracking woodwork, static shocks, and dry sinuses usually mean the house is running well under thirty percent relative humidity.
UV and air purification
Coil-mounted UV keeps biological growth off the evaporator, which is a real and specific benefit. Whole-house purifiers help, on top of good filtration rather than instead of it.
Ventilation
Tight houses need controlled fresh air. A ventilator brings it in deliberately and tempers it, rather than letting the house pull unconditioned air through whatever gap it can find.
Carbon monoxide detection
Non-negotiable in any house with combustion equipment. We check placement during heating service, and it costs nothing to ask.
Humidity Is the Delaware Problem
Zone 4A summers are humid. Add a house near the water in Lewes, Rehoboth, Dewey, or Bethany, or a beach rental that sits closed up between guests, and you get the conditions that grow musty smells and mildew on window frames.
Two things drive it. An oversized air conditioner satisfies the thermostat before it has run long enough to dehumidify, so the house ends up cool and damp. And a house that is tight enough to hold humidity but has no dehumidification strategy will hold it all season.
The fixes are unglamorous: right-size the equipment, run longer and slower cycles with variable speed or two-stage equipment, and add whole-house dehumidification where the load calls for it. See AC installation for the sizing side of that conversation.
How an Evaluation Goes
- We look at the equipment, the filter setup, and how the system is actually running
- We inspect accessible ductwork for leaks, crushed runs, disconnected boots, and undersized returns
- We check humidity levels rather than guessing from how a room feels
- We ask which rooms are the problem, because that narrows it faster than any instrument
- You get a plain list of what is wrong and what each fix costs, in the order that gives you the most relief per dollar
We will tell you when the cheap fix is the right fix. A media cabinet and sealing a few boots often does more than a four figure purifier bolted onto a leaky system.
Mark Sabean has been diagnosing these systems in Kent County since 1989, and the pattern almost never changes: the homeowner was quoted equipment when the ductwork was the problem. Our technicians are not paid on commission, so nobody here has a reason to sell you the expensive answer to the cheap question. Delaware license #36081.
Air Quality Questions
A one inch filter, every one to three months, sooner with pets or during heavy pollen. A four or five inch media filter typically runs six months to a year. Check it rather than trusting the calendar. A filter so loaded it bows in the frame is the single most common cause of no-cooling calls we get.
No, and this one costs people money. A high MERV filter in a one inch slot restricts airflow enough to hurt performance and, in winter, can trip the furnace on high limit. The right answer is usually a deeper media cabinet, which gives you better filtration and more surface area at the same time.
No. Duct cleaning earns its keep after construction or a remodel, after a rodent problem, or when there is visible contamination. Annual cleaning is a subscription rather than a service, and we do not push it.
Usually moisture sitting on the evaporator coil or in the drain pan, or return duct pulling air from a damp crawlspace. Coil-mounted UV helps with the first. Sealing the return fixes the second. If it is worse right when the system kicks on, that points at the coil.
Roughly forty to fifty percent in summer and thirty to forty in winter. Above sixty you get mildew and dust mites. Below thirty you get static, dry sinuses, and gaps opening in hardwood and trim. A cheap hygrometer tells you where you actually stand.