Heat Recovery Ventilators and How They Work

[@RedIgauna]

Great info and presentation! Thank you for differentiating between an HRV and ERV

[@MEPAcademy]

Glad it was helpful!

[@thomasbarr7812]

Excellent explanation and graphics. How much heat/cooling load does the ERV place on the home? Would it require re-sizing the heat pump? Thank you!

[@MEPAcademy]

That depends on several factors, one of which is the outside design temperature for winter and summer, and the other is the volume (CFM) of air that will be brought in. The fans may add a small amount of heat, but the biggest load is definitely the cooling or heating of the ventilation air brought in. Of course this is why a Heat Recovery or Energy Recovery unit is used to capture some of that energy. It's important to have fresh, ventilation air for good health. Contact a local HVAC Contractor or Mechanical Engineer so they can run a Heating and Cooling Load profile to get you the exact numbers to assist you with any decisions you're looking to make on Heat Pump sizing.

[@yohan2437]

What is the typical heat recovery efficiency of a polypropolene heat exchanger? It would seem that after a short period of running during a cold winter that the cool air would cause the heating to kick in resulting in high energy costs.

[@MEPAcademy]

Plastics are used for their corrosion resistant properties and lighter weight. You'll need to check with the manufacturer that you are thinking of using to see if they publish their efficiency values.

[@ياسرالفارس-ض9ح]

There is an easier, more useful and better way than digging all of this just for the sake of extending pipes, and it can be used anywhere on the earth under special conditions according to each region and at a lower cost. But the idea needs support from anyone I might partner with in this innovation

[@AnwarSharmit]

Is it ok to connect the return (contains contaminates) to the HR supply which will passes through the AC filters (collects dust only not other contaminates) and supplied back to the space?

[@MEPAcademy]

We're assuming you're discussing a residential project. The supply and return should be connected as required by the manufacturer and function as normal. The Heat Recovery Ventilator has another purpose and that is to recovery heat that would otherwise be lost. This could be the recovery of heat that is being exhausted during winter, or the removal of heat coming in with ventilation air during summer. Hope this helps.

[@RyuMoto]

Are HRV's popular in dry hot areas like the Pacific SW? For years and years I've wanted a filtered ventilation system that did not require an air conditioner. For most parts of the year (at least 2/3rds of the year) the evenings are nice and cool (60-70's F) while the days are hot. The evening air should be allowed into the home during times when hot air is warmer in the house vs. ambient air outside. However, most homes here in SoCal appear to be super leaky. Dust and pollen is also a big problem here. Just wondering if an HRV is appropriate to use in this climate and will this have the potential to introduce even more fine dust/pollen into a home that is "leaky" by nature.

[@MEPAcademy]

The heat recovery ventilator can pre-cool the incoming air if you're using air conditioning. Without air conditioning then you might want to limit the time it runs during hot dry days, and run it in the evening when the outdoor air temperature drops. As for indoor air quality, the HRV's are great at bringing in fresh air. In most area's the indoor air is more contaminated than the outdoor air due to cleaning products, cooking, building materials off-gassing, etc. I would work on sealing your home, and if you use an HRV, make the home slightly positive (more Supply Air than Exhaust air), this will help force air out of the leaks as best as possible, but wind pressure outside and other factors will effect infiltration. Another system approach would be to use a Whole House fan to bring in fresh air when the outside temperature drops to an acceptable level. Also, use a good quality filter, at least a MERV-13 if your system can handle the static pressure. See our other video on filters if you need a refresher. kzbin.info/www/bejne/hWO6mqeqp5x-pMk

[@maverickcalisse]

What prevents mixing of the air supply and exhaust in the core where they meet ?

[@MEPAcademy]

In these type of Heat Recovery Ventilators the air paths don't touch as there is some form of medium that separates the air streams. During operation, the exhaust air from the building passes over one side of the wheel, transferring heat and moisture to the matrix material. At the same time, fresh outside air is drawn through the other side of the wheel, absorbing heat and moisture from the matrix. The two air streams do not mix, but their energy is transferred through the matrix.

[@dc5duben96]

the video was helpful, thanks!

[@MEPAcademy]

Glad it helped!

[@yvettemcleod2196]

Thanks excellent information

[@MEPAcademy]

Glad it was helpful! Thanks for watching.

[@BonifaceOduor-r5o]

love this

[@MEPAcademy]

Thanks

[@LeA1ex]

excellent!! thank you!

[@MEPAcademy]

You're Welcome.

[@anvarahemadmansuri2414]

will this ERV work for an environment wherein humidity is constantly as high as 70-80%. I am from India, Gujarat, and the summers are very long since past 2 decades; lasting 10 months. rest of the 2 months, it is absence of high temperatures and a little bit lower humidity (still 40-60%)

[@MEPAcademy]

Energy recovery wheels, also known as enthalpy wheels, can work in environments with high humidity levels (such as 70-80%), but there are several important factors to consider such as humidity transfer, reduced efficiency and condensation risk. The design should consider a desiccant coating and pairing the wheel with some form of dehumidification to control excess moisture.

[@YAHIYAPOCHENGAL]

is toilet exhaust air allowed to recover ERV

[@MEPAcademy]

You can use toilet exhaust with an ERV or HRV, just check with the manufacturer to make sure their brand allows it.

[@CMCraftsman]

All major brands recommend using the ERV to exhaust the bathroom. In fact, we no longer install exhaust only fans in bathrooms in new construction here. The ERV takes care of it.

[@Grace-eq4lr]

Why did the ventilation fan in my house suddenly stop? I set the timer for an hour, but it only worked for a few minutes and then suddenly stopped. I tried it many times and it was the same every time. What is the reason?

[@MEPAcademy]

Could be a bad timer or something else. You need to have a technician look at it, as its impossible to determine without being there.

[@tombouie]

Well-Done

[@MEPAcademy]

Thanks for watching.

[@ياسرالفارس-ض9ح]

There is an easier, more useful and better way than digging all of this just for the sake of extending pipes, and it can be used anywhere on the earth under special conditions according to each region and at a lower cost. But the idea needs support from anyone I might partner with in this innovation

[@MEPAcademy]

Not sure how that applies to Heat Recovery Ventilators, but we're open to hear about it.

[@MillaLarissa]

The air to Air Heat exchanger of a Air conditioner is the engine from this machine ventilators

[@MEPAcademy]

Yes, you're correct. It's important to capture the energy that was already used to produce heating or cooling for the occupied space before it gets exhausted.

[@ياسرالفارس-ض9ح]

@@MEPAcademy Thank you very much. What is the name of the program you used to create this video?

[@israelquintanilla2784]

Someone had this into their home and had tons of dust inside. Don’t see a reason for this filter didn’t do the job either and ductwork was always dirty coming from outside.

[@MEPAcademy]

Thanks for the comment. As you know filters are rated for their different efficiencies. Need to use a filter that is appropriate for the conditions, while also considering the static pressure drop. There are many reasons a filter fails, including not being properly sealed around its perimeter.

[@matthewsachaullymce279]

I think the colouring is not right… in summer condition the incoming air would better colored as red/orange as it represents warm air from outside… IMHO 🙏🏻

[@MEPAcademy]

Yes the color may not represent the temperatures correctly, but as long as the theory is communicated we'll have to go with that for now, and be more careful on future videos that the color better represents the temperature. Thanks for the reminder.

[@matthewsachaullymce279]

@@MEPAcademy you are most welcome, looking forward for your new videos… 🙏🏻😃