Canister or Reservoir? Understanding Central Steam Humidifiers Better

February 4, 2022

Feb 2022 Blog Many of our readers may already know that of the types of central humidifiers available for installation on forced air (ie. furnace) heating systems, steam-powered units are the most effective at achieving and maintaining desired indoor humidity levels, far surpassing the capabilities of standard bypass and power humidifiers. In the relatively arid Colorado Front Range, many of us also appreciate the numerous benefits that proper humidity levels provide, from improved health and comfort, to much more.

Which type of central steam humidifier is best for your home’s furnace system? In this blog, we are going to talk a little bit about the two predominant designs of central steam humidifiers, their differences, what team prefers, and why.

What Are the Common Types of Central Steam Humidifiers?

Aprilaire 800 Steam Humidifier Internal First, there’s the ‘reservoir design’ (not pictured), which typically features a stainless steel water reservoir with an immersed heating element and a float valve to replenish the water supply as it gets low. There’s also a safety float switch to protect the unit from operating in the event the water level gets too low. Reservoir-type steam humidifiers are designed to be installed under existing horizontal ducting. Most units are available with an optional automatic-flush timer feature to help reduce stagnant water and the buildup of hard-water deposits in the reservoir. Depending on your home’s water supply, it might make sense to use an independent (or whole-house) water treatment product for the water supplying these units.

Next, there’s the ‘canister design,’ which has continued to grow in popularity over the past two decades, with reservoir units trending downward. Although there are several canister-style brands to choose from, they all have a central design element in common: a replaceable, self-contained canister in the heart of the unit that houses an electrode, where water is boiled and steam is produced. The steam is then delivered from the unit directly into the ducting through a special rubber steam hose; canister-style models are more versatile than many types of humidifiers when it comes to where and how they can be installed; this is due to the way the steam is produced and delivered.

Aprilaire Logo - Feel Good InsideNotably, the electrode technology doesn’t require specially purified or filtered water. In fact, according to our steam humidifier manufacturer of choice, Aprilaire, electrode technology requires impurities in the water to promote the transfer of electricity.

How Does Maintenance for Reservoir vs. Canister Designs Compare?

When it comes to reservoir-style central steam humidifiers, most manufacturers recommend cleaning the reservoir as frequently as every one to three months during the heating season, depending to a large extent on the water supplying the unit. Our service team has found that because there are immersible heating elements used in these units, they tend to have performance and maintenance issues due to hard-water deposits if not maintained consistently. In general, heating element failure in reservoir units may occur more frequently than some homeowners find acceptable.

Manufacturers of all canister-style units typically recommend replacing the steam canister annually. While the labor to service the unit is relatively quick and straightforward, the cost of the canister itself is considerably more than the media pads used in standard units. But as we’ve stressed previously, steam units are a much higher performing central humidifier option. Otherwise, there’s very little cleaning (and zero scrubbing from hard-water deposits) required.

Which Design of Steam Humidifier Performs Better?

AprilaireWhile maintenance needs and costs are naturally an important factor when choosing a central steam humidifier, don’t forget that performance expectations and ‘walking the walk’ can make all the difference. The most popular reservoir-style humidifiers in the residential industry over the past 20 to 30 years have evaporative ratings ranging from about 14 to 17 gallons per day. The top performing canister model available today – and the model recommended by our team – the Aprilaire 800 Whole-House Steam Humidifier has an evaporative rating of up to 34.6 gallons per day, with six customizable output levels to match the specific humidification needs of the homes they serve.

Few models currently available come close to approaching the model 800 for performance and versatility, and this premium central humidifier continues to be the choice of our team for homeowners who desire the most that a central humidifier can provide.

Here are a few more reasons why we recommend the Aprilaire Model 800 Whole-House Steam Humidifier:
  • User- and servicer-friendly digital control and diagnostic monitoring panel
  • Automatic drain-and-fill cycle to help maintain optimal electrode and steam production
  • Auto-drain feature to assure fresh water is delivered to the unit after extended (over 72 hours) periods of non-use
  • Sophisticated operating-time monitor to coordinate drain/refill cycles, respond to periods of non-use, and track canister life

Lennox Healthy Climate Solutions LogoSomething else to consider when choosing a central steam humidifier is that most units, both canister and reservoir models, are available in 120 volt or 240 volt models. The 240 volt models have proven to be more satisfactory for homeowners because of their higher evaporative ratings. However, installation of these units often requires additional electrical circuit work. Regardless of the greater cost, many of our customers choose the 240 volt models.

Expert Central Humidifier Advice for Denver-Boulder Homes

Homeowners in the Denver-Boulder metro area have been trusting our team at Save Home Heat Company to provide expert home services for over 40 years. We are very experienced and knowledgeable with the full range of central humidifiers designed to install on central furnace systems. Please reach out to us for friendly, low-pressure, expert advice on central humidifier options that make sense to consider for your home – and for professional installation you’ll be happy with for many years to come.

Please contact me to discuss a central humidifier for my home!

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