Zehnder ComfoAir 70 Lets You Breathe Easier in a Smaller Space
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Do you hear that? Come a little closer and quiet down. Now do you hear it? That’s the sound of a Zehnder ComfoAir 70 (CA 70) providing fresh air to your studio apartment, your home office, or small workout space. Perhaps you’re more familiar with the (almost no) sound of a Zehnder system in a larger home, regardless the end goal is the same; To remove stale used up air from your living space and replace it with fresh filtered air while recovering the heat from exhausted air. Wondering how you can achieve this feat in your own small space without convoluted ducting and having to tear out drywall? Perhaps your building a new tiny home and need a way to ventilate while conserving heat? Read on to find out what benefits the ComfoAir 70 can breathe into your space.
Is the Zehnder ComfoAir 70 for me?
Is the ComfoAir 70 the right unit for you? If you are retrofitting an existing small space with improved insulation and air tightness, then yes, this could be the right unit for you. Other prospective use cases could be if you are constructing a commercial office space with individual offices that need localized ventilation, even a multifamily project with many small units can benefit from the compact and efficient design of the CA 70. That’s one of the great things about this little unit, it is incredibly versatile! Let’s say you have a home office that needs that little bit of extra ventilation, but you don’t want or need to buy a whole home ventilator. Maybe you already have a whole home system, but due to changing circumstances are now using a previously under used space that wasn’t part of the original ventilation plan. The answer to your situation could very well be the CA 70.
With its simple package, the CA 70 was designed with the retrofit market in mind. Indeed, the self-contained state of the art design makes it a breeze to install and start reaping the benefits of fresh air. This unit utilizes an Enthalpy Exchange Core for heat and moisture recovery and control. This makes it perfect for maintaining comfort and proper humidity levels in a space such as a studio apartment where living and cooking areas aren’t separated. Boiling a pot of pasta and it’s fogging up your windows? Can’t open the window for extra ventilation because it’s too cold outside? Put the ComfoAir 70 in its boost mode and it can handle that extra moisture for you, without sacrificing your warm air to the outside.
How does the Zehnder ComfoAir 70 work?
“How does one little machine do all that though?” you might be asking yourself. The ComfoAir 70 shares the same technology with its bigger cousins such as the ComfoAir 350 and the Q series of recovery ventilators. Using the enthalpy exchange core, as much as 90% heat recovery efficiency and 84% humidity recovery efficiency can be reached. These high efficiencies are achieved at the lowest fan setting, (which uses only 4 watts!) which allows the air more time in the core to achieve the energy exchange. What about the above situation of excess humidity needing to be vented? By temporarily boosting the fans to the highest speed, air is moved through the core at a quicker pace, preventing some of the exchange from happening. This has the effect of bringing the humidity recovery rate down to 54%, which means more of the moisture is being vented out of the space and is being replaced with dry outside air. While this does also bring the heat recovery efficiency down to ~71%, boost runs for such a short time that the overall impact on heat recovery is minimal.
As you can see, the enthalpy exchanger is a key part of keeping these units efficient in various conditions, but that’s only part of the picture. To keep power consumption to a minimum, the ComfoAir 70 uses a pair of fans driven by ultra-energy-efficient EC direct-current motors. An electrical nerd could gush on and on about these, but numbers can do the talking here. At the lowest setting, the ComfoAir 70 uses a negligible 4 watts, that’s 300x less than a toaster uses! Of course, you don’t leave your toaster on all day and night (we hope!), nor does the average person run an ERV at the lowest setting 24/7. More realistic settings see the unit using 5 – 9 watts average, and 17 watts for temporary boost speeds. What is the energy use of another typical household item that runs 24/7? A ceiling fan! On average these use 120 watts to run at full speed, so even at the lowest setting this can be as much as 40 watts! The obvious winner in efficiency here is the EC direct-current motors.
Why do I need one?
Zehnder ComfoAir 70’s sleek design ensures that it will complement your home’s design while supplying needed fresh air.
That’s a great question. There are many benefits to installing a recovery ventilator in your living space, and increased air quality is just one of them. It is a fact that more and more homes are being built to higher airtightness tolerances, and this is great for keeping energy in the home! A side effect of these airtight constructions is that it becomes harder for moisture that makes its way inside the home to get out. While we don’t want the inside of our homes to be a bone dry 0% Relative Humidity (RH), excess moisture can be harmful to the building’s longevity and health, and can lead to mold/mildew which is harmful to YOUR health.
Even just occupying an indoor space creates humidity from our breathing. This may not seem significant, but in a small space such as a Tiny Home, it can quickly add up if it has nowhere to go, especially when you start to include pets and daily activities. By using a recovery ventilator like the CA 70, you can rid your space of the excess moisture while not needing to practically cut a hole in that air barrier you just spent so much on, and keep your heat inside. This is because the heat from the exhausted air is transferred to the incoming air stream as it passes through the core. Ultimately, this saves you money since your heating system doesn’t need to heat frigid outside air.
You convinced me, but how easy is the Zehnder ComfoAir 70 to install?
The CA 70 can be installed in a single room fashion, or optionally with bathroom or kitchen extract ducting using the second room adapter, a unique feature you won’t find on similar units. The unit must be installed on an exterior wall. A roughly 10” diameter hole is cut in the wall, and a structural wall mounting pipe is inserted to support the unit. It is important to note that the thickness of the wall for this unit must be a minimum of 12”, so there may be a need to fur out your wall to accommodate the extra thickness. After the wall mounting pipe is installed and 230v mains power is ran to the location, the inside half of the unit is inserted and connected, and the insulated air duct tube is trimmed to length. Then it’s as simple as affixing the weather resistant exterior wall panel to the outside connection! And you thought they wouldn’t address the big hole you just cut in your wall. This kit comes with a self-adhesive swelling sealing tape that will keep the housing air-tight, and the built-in shutters will automatically close when the fans aren’t running in standby mode, keeping your interior space air-tight.
The inside half of the CA 70 will house the supply and return ports, along with the controls for the unit. There is an optional remote-control panel, but what is really exciting are the add-on modules for humidity, VOC, or CO2 sensing! These can be installed at the factory and expand the capabilities of the CA 70 to sense changes in the selected variables and adjust fan speeds accordingly. Imagine your CA 70 being able to sense when you are taking a shower and ramping up the fan speed. You would never have to bother with flipping on a noisy exhaust fan ever again. The humidity add on module can achieve just that with its included temperature and humidity sensors constantly polling the air to calculate relative humidity and adjusting as necessary.
The VOC and CO2 modules come with a humidity sensor and have the added benefit of sensing a rise in CO2 or VOC levels. There is a very close correlation between the levels of CO2 and VOCs, but if desired both options may be combined. The unit will prioritize fan speed adjustment according to whichever is the higher level. The implication here is that the CA 70 will now be able to run in Automatic Mode and optimize indoor air quality based on input from the installed sensors. At that point, the only time you would ever need to interact with the unit is to change the filters every six months. Zehnder even made that hard to forget by including an LED right on the unit that will illuminate when it’s time to change filters.
The exterior wall panel is the last part to be installed. This panel has the intake and exhaust located on either side of a sleek looking cover, available in several styles ranging from plastic to stainless steel. Worried that the intake and exhaust are too close together and could lead to air stream cross contamination? Worry not! Much work and design went into ensuring cross contamination of incoming and outgoing air was kept to a minimum. In fact, there was an extensive study done on it and the results clearly show that this design works just as well as a typical recovery ventilator that has intake and exhaust spaced ~10’ apart. Once the exterior cover is installed, the CA 70 is ready to get to work bringing you fresh air without sacrificing comfort!
OK, how do I get one?
Small Planet Supply has ComfoAir 70s in stock right now! You may remember them being available a few years back, and then disappearing. Indeed, these newly arriving units are a revision of the older series. There was a necessity to adjust the power supply and it subsequently needed to get its UL listing updated. That time off the market allowed Zehnder to perform other adjustments to improve performance and quality. The CA 70 is even Passive House certified, so there’s so much value in this small package!
Ready to put in an order for your new ComfoAir 70? You can call our warehouse (855-367-7442) to purchase a system or send us an email and we’ll contact you to take your order. . Still not sure if this is the right recovery ventilator for you? We offer complimentary telephone consultations with our specialists to help answer your questions. Or visit Small Planet Supply’s Zehnder page to learn more about Zehnder HRV and ERV systems.
