Aprilaire 700 vs 800: Which Whole-House Humidifier is the Best Investment?

Dry winter air does more than just crack your skin and irritate your sinuses; it can actively damage your home’s wood floors and furniture. If you are debating between the Aprilaire 700 vs 800, the decision ultimately comes down to your home’s heating source and your budget. The Aprilaire 700 is a fan-powered evaporative unit best suited for standard gas furnaces and budget-conscious homeowners, while the Aprilaire 800 is a steam humidifier that offers superior performance for heat pumps, larger homes, and those demanding precise humidity control regardless of air temperature.

Choosing the wrong unit can lead to wasted water, high electric bills, or a system that simply can’t keep up with the dryness. In this guide, we will break down the technical differences, installation requirements, and long-term costs to help you decide which model belongs in your utility room.

The Core Difference: Fan-Powered vs. Steam

While both units are designed to humidify your entire house via your HVAC ductwork, the technology they use to generate moisture is fundamentally different. Understanding this mechanism is the first step in sizing the right unit for your needs.

Aprilaire 700: Fan-Powered Evaporative

The Aprilaire 700 is a “fan-powered” evaporative humidifier. It works by trickling water over a specialized metal mesh (the water panel). A built-in fan pulls warm air from your furnace, pushes it through this wet panel, and circulates the now-humid air back into your home. It relies heavily on the heat generated by your furnace to evaporate the water effectively. If your furnace isn’t blowing hot air, the 700 struggles to produce significant humidity.

Aprilaire 800: Steam Canister

The Aprilaire 800 is a steam humidifier. Instead of relying on air movement or furnace heat, it boils water inside an internal canister using electrodes. This creates pure steam that is injected directly into your ductwork. Because it creates its own heat, the Aprilaire 800 can humidify your home even when the furnace is running on a low “fan-only” setting or if you have a heat pump that produces cooler air.

Comparison at a Glance: Aprilaire 700 vs 800 Specs

To give you a clear picture of how these two heavyweights stack up, we’ve compiled the technical specifications into the table below. Note the significant difference in electrical requirements and daily capacity.

Feature	Aprilaire 700 (Fan-Powered)	Aprilaire 800 (Steam)
Technology	Evaporative (Water Panel)	Steam (Electrode Canister)
Capacity (GPD)	Up to 18 Gallons Per Day	11.5 to 34.6 Gallons Per Day
Coverage Area	Up to 4,200 sq. ft.	Up to 6,200 sq. ft.
Electrical Draw	Low (0.7 Amps @ 120V)	High (11.5 – 16 Amps @ 120V/240V)
Water Usage	High (Constant trickle to drain)	Efficient (Boils water, minimal waste)
Maintenance Cost	Low ($15-$20/year for panel)	Moderate ($50-$100/year for canister)
Best Heat Source	Gas/Oil Furnace (Hot Air)	Heat Pump, Geothermal, or Gas

Performance and Efficiency Deep Dive

When comparing the Aprilaire 700 vs 800, raw specs don’t tell the whole story. Real-world performance varies heavily based on your home’s infrastructure.

Water Efficiency and Waste

The Aprilaire 700 is a “flow-through” humidifier. This means that for every gallon of water it evaporates into the air, several gallons trickle down the drain. While this flushes away minerals and keeps the pad clean, it can feel wasteful if you are on metered water. In contrast, the Aprilaire 800 is far more water-efficient during operation. It boils the water inside the canister, converting nearly 100% of the water it draws into steam. However, it will periodically drain and refill to manage mineral concentrations, but the total volume lost is significantly less than the constant trickle of the 700.

Electrical Consumption

This is where the costs flip. The Aprilaire 700 consumes very little electricity—about as much as a standard lightbulb—because it only powers a small fan. The Aprilaire 800, however, acts like a giant kettle. It requires significant amperage to boil water. If you run the 800 on 240V (which is recommended for maximum output), you will notice a distinct increase in your monthly electric bill during the winter months.

Suitability for Heat Pumps

If you have a heat pump, the Aprilaire 800 is the clear winner. Heat pumps typically output air at 85°F to 95°F, which is not hot enough to effectively evaporate water in the Aprilaire 700. The 700 might technically “work,” but it will struggle to raise the humidity above 30% on cold days. The 800 creates its own steam regardless of your duct temperature, ensuring your expensive Palmetto Road flooring doesn’t warp from extreme dryness.

Installation Requirements

Installation complexity is a major factor if you plan to DIY this project. One unit requires simple duct cutting, while the other might require an electrician.

Installing the Aprilaire 700

The 700 is designed to be mounted directly onto the supply (warm air) plenum of your furnace. It requires cutting a rectangular hole in the metal ductwork. You will need to wire it to a standard 120V outlet (or hardwire it) and run a humidistat line. The most critical part is ensuring the unit is perfectly plumb and level. If you mount it crooked, much like side-by-side refrigerator doors that are not flush, the water distribution tray won’t feed the panel evenly, reducing efficiency.

Installing the Aprilaire 800

The 800 offers more flexibility but requires more skill. The main canister unit can be wall-mounted away from the ductwork, with a steam hose running to a dispersion tube installed in the duct. This is excellent for tight utility rooms. However, the electrical requirement is steep. You ideally need a dedicated 240V circuit installed by an electrician. While it can run on 120V, its output drops significantly (from ~34 GPD down to ~11.5 GPD), largely defeating the purpose of buying the steam unit.

Maintenance: Panel vs. Canister

Both units require annual attention, but the costs and procedures differ. Neglecting maintenance on either will lead to mold growth or total system failure.

For the Aprilaire 700, maintenance is incredibly simple. You remove the cover, slide out the old “Water Panel” (usually Model #35), and slide in a new one. This costs about $15 to $20. It’s easier than fixing an old Toro 724 snowblower; it takes less than five minutes. You should also clear the orifice and drain line of any sediment.

The Aprilaire 800 requires replacing the entire steam canister (Model #80). Because the electrodes are inside the canister, they get coated in mineral scale over time. The unit will eventually stop producing steam and a service light will blink. These canisters cost between $50 and $100. While more expensive, the “pop-out, pop-in” nature of the canister means you don’t have to scrub mineral deposits—you just throw the whole scaled-up container away.

Common Problems and Troubleshooting

Even top-tier equipment fails. Here is what typically goes wrong with these models:

• Aprilaire 700 Leaks: This is almost always due to a clogged drain line or a scale-filled water panel. If the water can’t flow down through the mesh, it splashes outward.
• Fan Noise (700): Over years, the fan motor on the 700 can develop a rattle. It is replaceable, but audible.
• Aprilaire 800 Service Light: If the light blinks red, the canister is likely at the end of its life. If it blinks shortly after a new installation, it might be due to water with too low mineral content. The 800 needs some conductivity in the water to work; it actually struggles with pure distilled or highly filtered reverse-osmosis water.
• Steam Hose Sag (800): If the steam hose isn’t supported properly, condensation can pool in a low spot (a trap), blocking the steam and causing the unit to shut down.

Frequently Asked Questions: Aprilaire 700 vs. Aprilaire 800

What is the primary difference between the Aprilaire 700 and the Aprilaire 800?

The fundamental difference lies in the technology used to generate humidity. The Aprilaire 700 is a fan-powered evaporative humidifier that blows air through a wet water panel, relying on the heat from your furnace to evaporate the water. In contrast, the Aprilaire 800 is a steam humidifier that uses electrode canisters to boil water directly, creating steam independently of your home’s heating system. This allows the 800 to deliver moisture even when the furnace isn’t actively heating the air.

Which humidifier provides better coverage for large homes?

The Aprilaire 800 is generally the better investment for larger properties. While the Aprilaire 700 is capable of handling homes up to 4,200 square feet with a capacity of 18 gallons per day (GPD), the Aprilaire 800 offers a significantly higher output. Depending on the electrical voltage used during installation (120V or 240V), the 800 can treat homes up to 6,200 square feet with a capacity ranging from 11.5 to 34.6 gallons per day.

My home has very hard water. Which model should I choose?

The Aprilaire 800 is the superior choice for homes with hard water. In the Aprilaire 700, mineral deposits can clog the evaporative water panel quickly, reducing efficiency and requiring frequent replacements. The Aprilaire 800 uses a steam canister system where the minerals remain trapped inside the canister as the water boils. When the canister reaches the end of its life, you simply replace the entire unit, preventing scale buildup on the device itself.

Is the Aprilaire 800 more expensive to run than the Aprilaire 700?

Yes, the Aprilaire 800 typically has higher operating costs due to electricity consumption. Because it boils water to create steam, it draws significant amperage (up to 16 amps at 240V). The Aprilaire 700 is extremely energy-efficient, using only a small amount of electricity to run a fan. However, the 700 does consume more water because it uses a flow-through process where excess water drains away, whereas the 800 converts nearly all water it takes in into steam.

Do both humidifiers require a hot air supply to function effectively?

No. The Aprilaire 700 performs best when installed on the supply plenum where hot air from the furnace facilitates evaporation. If you have a heat pump with lower air temperatures, the 700 may struggle to output its full capacity. The Aprilaire 800 creates its own steam regardless of air temperature, making it the ideal solution for homes with heat pumps, geothermal systems, or for homeowners who want to maintain humidity levels without running the heat.

How does the installation difficulty compare between the two units?

The Aprilaire 700 is generally easier to install for a typical forced-air system, as it mounts directly onto the supply duct and plugs into a standard outlet (though it requires low-voltage wiring to the furnace). The Aprilaire 800 offers more placement flexibility because the steam canister can be mounted remotely on a wall, with a steam hose running to the duct. However, the 800 requires a dedicated electrical circuit and hardwiring, which usually necessitates a professional electrician.

What are the maintenance requirements for the Aprilaire 700 vs. the 800?

Both units require annual maintenance, but the process differs. The Aprilaire 700 requires you to replace the #35 Water Panel typically once per year, or more frequently in hard water areas, and you should clean the distribution tray to ensure even water flow. The Aprilaire 800 requires the replacement of the steam canister (Model 80) usually once per heating season. The 800’s “automatic digital control” will actually signal when the canister needs to be changed based on conductivity levels.

Which unit is more water-efficient?

The Aprilaire 800 is significantly more water-efficient. It is a 1-to-1 system, meaning practically every drop of water that enters the canister is boiled into steam and added to your air. The Aprilaire 700 is a flow-through system that constantly flushes water over a panel to prevent mineral buildup; consequently, a significant amount of water does not evaporate and must be directed to a floor drain.

Can the Aprilaire 700 be installed if I don’t have a floor drain nearby?

Installing an Aprilaire 700 without a floor drain is difficult and not recommended. Because it is a flow-through system, it produces a steady stream of wastewater while running. If a gravity drain isn’t available, you would need to install a condensate pump to move the water to a drain location. The Aprilaire 800 does not produce wastewater during operation, though it may flush a small amount of water occasionally to manage mineral concentrations, making drainage requirements slightly less demanding but still necessary.

Which humidifier is the better overall investment?

If you have a standard gas furnace, a home under 4,000 square feet, and want a cost-effective, energy-efficient solution, the Aprilaire 700 is the best value investment. However, if you have a larger home, expensive woodwork that requires precise humidity control, a heat pump system, or hard water, the Aprilaire 800 is the better investment despite the higher upfront and operational costs, as it guarantees consistent performance regardless of your HVAC system’s heating cycle.

Final Verdict: Which Model Should You Buy?

Deciding between the Aprilaire 700 vs 800 isn’t just about “good vs. better”—it’s about matching the equipment to your home’s infrastructure.

You should buy the Aprilaire 700 if:

• You have a standard gas or oil furnace that blows hot air.
• Your home is under 4,000 square feet.
• You want a budget-friendly installation and low annual maintenance costs.
• You have easy access to a floor drain near the furnace.

You should buy the Aprilaire 800 if:

• You have a heat pump, geothermal system, or high-efficiency furnace with low run times.
• You have a very large home (over 4,000 sq. ft.) or very high ceilings.
• You want precise humidity control to protect expensive woodwork, pianos, or art.
• You are willing to pay more for electricity to save water.
• You have limited space on your ductwork and need a remote-mount solution.

Ultimately, for most standard homes with gas heat, the Aprilaire 700 is the workhorse that offers the best value. But for modern, high-efficiency homes where air temperatures are lower, the Aprilaire 800 is the only choice that guarantees consistent comfort.