Aprilaire
Aprilaire 700 Fan-Powered
The fix for the bypass units' one real flaw. A fan-powered humidifier has its own blower, so it can run independently of the furnace - on a mild day when the heat barely cycles, this one still humidifies and a 500 or 600 does not. It also needs no bypass duct, which makes it the easier install where the furnace is tight against a wall. Eighteen gallons a day, 5,300 sq ft claimed for a tight home, and around 3,000 for an average one by Aprilaire's own guidance. The load calculation lands at about 4,400.
The room-size claim, reconciled
4,434 sq ft supported · box says 5,300 sq ft
The box says 5,300 sq ft; the winter load calculation puts the output at 4,434 sq ft — an overstatement of about 20%, which is modest for this category.
What a year costs
one Aprilaire 35 water panel a season at roughly $25. Electricity assumes the rated 145 W for 12 hours a day across a 150-day heating season at 16¢ per kilowatt-hour.
Specifications
Maintenance profile
- Top fill
- No — tank comes off and goes to the sink
- Replaceable media
- Filter, replaced through the season
Facts, not a score. Which of these matter depends entirely on whether the unit ends up somewhere you will actually clean it.
Features
- 18 gal/day capacity
- Built-in blower - humidifies without waiting for the furnace
- No bypass duct needed
- Automatic digital humidistat
- One water panel a season
- 5-year warranty
Pros
- The only whole-house evaporative here that can humidify when the furnace is idle, which is the specific complaint owners of bypass units raise
- No bypass duct makes it fit in mechanical rooms where a 600 will not
- Highest evaporative capacity Aprilaire makes, at $70 more than the 600
- Same $25 panel and same five-year warranty as the bypass units
Cons
- 145W whenever it runs, against 20W for a bypass unit that borrows the furnace blower
- The onboard fan is audible in a finished basement in a way a bypass unit is not
- Installation cost runs a little above the bypass models, typically $840-$1,560
- Still forced-air only - the fan solves the idle-furnace problem, not the no-ductwork one
- The 5,300 sq ft headline is for tight construction; Aprilaire's own average-home figure is around 3,000
What owners say
Summarised from owner discussions and long-form owner reviews. Nobody here has used this unit.
The answer to the bypass units' one real weakness. Because it carries its own blower, it humidifies on a mild day when the furnace is not cycling, and that is precisely the gap owners of 500s and 600s describe. In a well-insulated house or a mild climate, that difference is the whole purchase decision.
The costs are modest and predictable: real electrical draw whenever it runs, an audible fan near the furnace, and a slightly higher installation bill. Aprilaire's sizing guidance applies as it does to the bypass models — the headline square footage is the tight-construction figure and the realistic target for an average home is substantially lower.
What owners like
- The onboard blower means it humidifies when the furnace is idle, which is the specific complaint bypass owners raise
- Highest evaporative capacity Aprilaire makes, for modestly more than the 600
- Same $25 water panel and the same five-year warranty as the bypass units
- No bypass duct needed, so it fits mechanical rooms where a 600 will not
Common complaints
- It draws real power whenever it runs, against effectively nothing for a bypass unit that borrows the furnace blower
- The onboard fan is audible in a finished basement in a way a bypass unit is not
- Installation runs a little above the bypass models
- Still forced-air only, and still no per-room control
Questions owners ask
Is it worth the premium over the 600?
How much power does it use?
Will I hear it in a finished basement?
Aprilaire 700 Fan-Powered, head to head
Looked at alongside it
More from Aprilaire →
Aprilaire
Aprilaire 600 Bypass
The best-selling whole-house humidifier in North America, and the default recommendation from most HVAC contractors for a reason: seventeen gallons a day for $220 of hardware and $25 a year of water panels. The published 5,000 sq ft is the tight-construction figure, and Aprilaire says plainly that an average home of about 2,000 to 2,500 sq ft is the realistic target - a maker volunteering that its headline number applies to a minority of houses. The load calculation puts 17 gal/day at around 4,200 sq ft, neatly between Aprilaire's own two figures.
4,188 sq ft supported · box says 5,000 sq ft
Aprilaire
Aprilaire 500 Bypass
Bolted to the ductwork, plumbed to a water line, and never filled by hand again - that is the entire argument for going whole-house, and the Aprilaire 500 is the small end of it. A bypass humidifier borrows warm air from the supply duct, passes it through a wet evaporator panel, and returns it to the return duct; it only humidifies while the furnace is running, which is its main limitation. Twelve gallons a day matches the biggest portable console in this catalog, and the 3,600 sq ft claim sits about a fifth above what the load calculation supports. Aprilaire publishes separate figures for tight, average and loose construction, which is a more honest way to state coverage than anyone selling a plug-in unit manages.
2,956 sq ft supported · box says 3,600 sq ft
Aprilaire
Aprilaire 800 Steam
Nearly 35 gallons a day, which is twice the biggest evaporative here and three times any portable. A steam humidifier boils water with electrodes and injects the steam into the ductwork, so unlike every evaporative unit it does not care whether the supply air is warm - it makes its own heat. That is what lets it serve a 10,000 sq ft house, and it is also why it needs a dedicated 240V circuit and why installation runs $1,800 to $4,200. There is no water panel to buy, which is the one running cost it removes; the 11.5 kW it draws while steaming is the one it adds.
8,524 sq ft supported · box says 10,300 sq ft