A shock off the stair rail
Heat pump houses run the blower long and cool, and the zap you take from the metal stair rail or the car door is the giveaway. Every day means the air is well under 30 percent.
Herndon, Virginia
Whole-home humidifiers in Herndon.
For whole-home humidifier repair in Herndon, if the humidifier you have stopped working, finding out why is the $99 diagnostic visit. Call SwiftPro, rated 5.0 stars across 1,130 reviews, at (703) 997-9757, 24 hours a day, 7 days a week.
For whole-home humidifiers in Herndon, SwiftPro is rated 5.0 stars across 1,130 reviews and works under Virginia Class A contractor license 2705192276. Whole-home humidifiers in Herndon, where heat pumps outnumber gas furnaces and the fan-powered Aprilaire ends up on most of our installs. A new one is priced at your house, in writing, once we’ve seen the furnace, the ductwork and the nearest water line. Through October 31, code HUMID250 takes $250 off a humidifier plumbed into the ductwork.
- Priced in writing at your house
- Our own HVAC technicians
- Set and tested before we leave
5.0 stars across 1,130 reviews
A whole-home humidifier mounted on the supply duct above the furnace, with its own water line and drain.
Get your price in writing
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Licensed and insuredVirginia Class A contractor #2705192276
24/7 emergency serviceWe answer day or night, and we will tell you honestly when we can get there.
Our own HVAC installersA dedicated heating and cooling team, separate from our plumbers
Price in writing firstYou see every option priced before anything is ordered
What it costs
What a whole-home humidifier costs in Herndon.
We price it in writing at your house, the same way our whole-home humidifier page explains. More on the numbers in our humidifier cost guide.
Diagnostic visit, when the humidifier you have stopped working
$99
Whole-home humidifier installed on your furnace or air handler
Priced at your house, in writing, before any work
Coupon HUMID250, through October 31
$250 off the install
Prices checked .
What moves the price is the model and the path to it: a bypass model on an open basement furnace with a water line close by is the simple end, a fan-powered model in a tight closet with a long run for water and a drain is the other.
If the house already has a humidifier that stopped, we look at it first. Often it’s a crusted water panel, a closed saddle valve or a control that lost its wiring, and that’s a repair, not a new unit.
What’s different in Herndon
Herndon flips the usual order: heat pumps first, gas furnaces second.
Six in ten Herndon owners heat with electricity and under four in ten with gas, the reverse of most of Fairfax County. Electric here mostly means a heat pump, and a heat pump’s supply air leaves the register cooler than a furnace’s. A bypass humidifier leans on hot air to evaporate its pad, so on those systems we reach for the fan-powered 700-series Aprilaire, which moves its own air.
Look at the mix of housing and you see why a standard quote misses. Townhouses are 27 percent of Herndon’s owner homes and condos and apartments another 23, with nearly four in ten households renting. In a condo, the closet, the water supply and the drain often belong to the building. Ask your board before you call anyone, or you may pay for a design the association won’t let in.
The Town takes its water from Fairfax Water, mostly out of the Corbalis plant on the Potomac, and Corbalis ran from 70 to 185 mg/L of hardness through 2025. That is moderately hard water at the low end and hard at the top, and it leaves a chalky film on a humidifier’s water panel. Count on changing that panel each heating season. It comes out with two clips, and we will show you.
Herndon’s median owner home dates to 1981, and a lot of the stock is older than that, built before anyone worried about sealing a house. Those places lose moisture through every attic hatch and window frame, so the unit has to run harder. Downtown, inside the Town’s historic district, the Historic District Review Board approves most outside changes, which can include the outdoor temperature sensor, so check first. Our cost guide explains what moves the price.
Neighborhood by neighborhood
What fits on the system across Herndon.
Census figures for the owner-occupied homes in each place, and the humidifier that usually suits houses like them.
| Place | Median home built | Most homes are | Heated with | What usually fits |
|---|---|---|---|---|
| Franklin Farm | 1985 | single-family houses, about 9 in 10 | electricity, about 5 in 10 | A fan-powered model, since heat pump air runs cooler. |
| Herndon | 1981 | single-family houses, about 4 in 10 | electricity, about 6 in 10 | A fan-powered model, since heat pump air runs cooler. |
| Dranesville | 1984 | single-family houses, nearly all | electricity, about 6 in 10 | A fan-powered model, since heat pump air runs cooler. |
| McNair | 2003 | condo and apartment buildings, about 6 in 10 | gas, about 7 in 10 | A bypass model on the gas furnace’s ductwork. |
| Floris | 1990 | single-family houses, about 8 in 10 | gas, about 6 in 10 | A bypass model on the gas furnace’s ductwork. |
| Hutchison | 1979 | townhouses, about 5 in 10 | electricity, about 7 in 10 | A fan-powered model, since heat pump air runs cooler. |
| Sully Square | 2015 | condo and apartment buildings, about 6 in 10 | gas, about 6 in 10 | A bypass model on the gas furnace’s ductwork. |
By the numbers
Herndon houses, by the numbers
From the Census Bureau’s 2020 to 2024 survey. Median year built and heat count owner-occupied homes only.
The Town of Herndon
Inside the town limits. Floris, Franklin Farm, McNair and Dranesville, on the Fairfax County side, are counted by the Census as places of their own.
- Median home built1981 Census
- Built before 1980about 4 in 10 Census
- Built since 2000about 2 in 10 Census
- Most homes aresingle-family houses, about 4 in 10 Census
- Heated withelectricity, about 6 in 10 Census
- Rentedabout 4 in 10 Census
- Houses from the 80s and 90s often came with a builder’s humidifier on the furnace, and many of those are still on the duct, switched off.
- Many homes here are townhouses or condos with the system in a closet. A fan-powered model fits where there’s no room for a bypass duct, and in a condo the association may need to approve the water line.
The signs
When a Herndon house is too dry in winter.
Static every time you touch a doorknob
A zap off every light switch in January means the air in the house is well under 30 percent. Outdoor winter air holds little water, and heating it dries it further.
Floors and trim open up gaps
Wood gives up water in dry air. Gaps between floorboards, a cabinet door that sticks, or a piano that won’t hold its tuning through winter all point the same way.
Need whole-home humidifiers in Herndon?
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Choosing who does it
How to pick who installs a humidifier in Herndon.
Questions to ask anybody who quotes you one, us included.
Did they ask who owns the air handler closet?
In a Herndon condo or townhouse the closet, the water and the drain may all be shared. Whoever quotes should ask who signs off.
Did they ask where the water and the drain come from?
A humidifier needs a water line and, for most models, a drain. Whoever looks for both before quoting is the one who won’t surprise you on install day.
Did they say which kind, and why?
A bypass model, a fan-powered model and a steam model each suit different systems. Ask why theirs fits your furnace or heat pump, not just what it costs.
Two of our crew going over a work order before the day's calls.
From our Google reviews
What our customers say.
5.0 stars across 1,130 reviews. Read them on our reviews page.
Moisés’ HVAC work is exceptional. He installed a return that completely resolved a static build up problem we had. He also installed a whole house humidifier that we are very pleased with. I’d trust SwiftPro for any of my HVAC needs!
- 5.0stars across 1,130 reviewsHow we count them
- ABBB Accredited, A ratingCheck it on bbb.org
- 2026Voted a Nextdoor Neighborhood Faves winner two years running: 2026 in 30 Northern Virginia neighborhoods, 2025 in Emerald Chase (Herndon) and Hunters Run (Chantilly)See it on Nextdoor
- #1BusinessRate Best of 2026: the top-ranked heating contractor in Fairfax, VirginiaSee our BusinessRate score
- Class AVirginia contractor, license #2705192276Look it up with DPOR
Where we work
Whole-home humidifiers in every Northern Virginia town we serve
Next door to Herndon: Reston, Sterling, Great Falls, Oakton and Chantilly.
Fairfax County
Arlington County
Loudoun County
Prince William County
Fauquier County
Stafford County
Every town on one page
Questions
Humidifier questions from Herndon.
Why do you put fan-powered units on so many Herndon systems?
Heat pump air isn’t warm enough to do much for a bypass unit. The fan-powered one has its own air moving through it, so it works with cooler supply air.
How often do I change the water panel?
About once a season, more often on hard water. It’s a ten minute swap, and we’ll show you where it is.
How much is a whole-home humidifier in Herndon?
It’s priced at your house, in writing, because the model and the work depend on your system, your ducts and where the water line is. If you have one that stopped working, the diagnostic visit is $99.
What humidity should the house be at in winter?
The EPA says keep indoor humidity between 30 and 50 percent. On the coldest nights we run it nearer the low end so windows don’t sweat, and an Aprilaire with an outdoor sensor turns itself down for you.
Ready when you are
Find out what your house needs.
Call, or send the form at the top. We look at the furnace, the ducts and the water line, and you get the price in writing before any work starts.
SwiftPro Heating, Cooling & Plumbing
4230 Lafayette Center Dr N, Chantilly, VA 20151
44679 Endicott Dr, Suite 211, Ashburn, VA 20147
SwiftPro Plumber & Water Heaters
4200 Lafayette Center Dr, Suite N, Chantilly, VA 20151
Virginia Class A contractor license #2705192276
SwiftPro Heating, Cooling & Plumbing is a licensed, BBB Accredited (A rating), independently owned heating, cooling and plumbing company in Chantilly, serving Herndon and the rest of Northern Virginia. Virginia contractor license #2705192276. 5.0 stars across 1,130 reviews on Google, Angi, Yelp, the BBB and Facebook. SwiftPro maintains a dedicated HVAC team and a dedicated plumbing team.
From SwiftPro Heating, Cooling & Plumbing in Chantilly. Housing figures are the Census Bureau’s American Community Survey, 2020 to 2024, for each place named; permit, water and sewer facts link to each office’s own page and were checked in September and October 2026.