I bought a co2 monitor for greenhouses. I think indoor air standards say c02 should not exceed 1,000 in a properly ventilated home. We were always at around 1,000 to 1,300. After installing a fantec erv the house is at about 650 on average using the lowest eco setting of 20 minutes per hour of air exchange.
New Construction HVAC decisions. Geothermal vs. alternatives with upgraded envelope.
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I bought a co2 monitor for greenhouses. I think indoor air standards say c02 should not exceed 1,000 in a properly ventilated home. We were always at around 1,000 to 1,300. After installing a fantec erv the house is at about 650 on average using the lowest eco setting of 20 minutes per hour of air exchange.
/ New Construction HVAC decisions. Geothermal vs. alternatives with upgraded envelope.
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deezler
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My ERV is only 170 watts with the fan on high. We usually run it on low for 40 mins/hour (maybe 50 watts?). Negligible impact on electricity bill, especially considering you get nice fresh air supplied from it. Our house was built super tight, all casement windows, caulked framing seams, taped sheathing and exterior insulation, etc. An ERV was absolutely mandatory and frankly, I think should be required equipment on all new homes (ok, perhaps location dependent).
We also use a weather station (netatmo) to monitor indoor CO2. If we turn off the ERV, it can spike to 2000+ ppm of CO2 fairly quickly. The other benefit to my woodstove, however, is that it pulls a nice draft through the exterior door seal gaps (finds all the "not tight" bits) and keeps the air fresher in the house also. With the ERV and woodstove running, we stay in the 600-900 ppm range typically (3 humans, 2 cats, one dog in 1700 sq ft, vaulted ceilings).
CO2 of 1000-2000 ppm is not inherently dangerous, but its a great indicator of overall air quality. IE, more CO2 indicates less oxygen, and greater concentrations of other VOCs. Whereas low CO2, means you are venting properly.
We also use a weather station (netatmo) to monitor indoor CO2. If we turn off the ERV, it can spike to 2000+ ppm of CO2 fairly quickly. The other benefit to my woodstove, however, is that it pulls a nice draft through the exterior door seal gaps (finds all the "not tight" bits) and keeps the air fresher in the house also. With the ERV and woodstove running, we stay in the 600-900 ppm range typically (3 humans, 2 cats, one dog in 1700 sq ft, vaulted ceilings).
CO2 of 1000-2000 ppm is not inherently dangerous, but its a great indicator of overall air quality. IE, more CO2 indicates less oxygen, and greater concentrations of other VOCs. Whereas low CO2, means you are venting properly.
Ours is set for 20min per hour. Current Co2 monitor is at 705ppm at that setting. Very minimal energy usage as deezler noted. Ours is tied into the duct system so the erv and hvac fan both run at the same time to distribute fresh air to all rooms. Total usage about 200 watts combined which equates to about $6 per month of electric usage at my rates if I've done the math correctly.
On a side note, if you ever wonder if an ERV is necessary put your nose to the exhaust side of the erv coming out of someones home. It was amazing to me how not so fresh the air smells that it is exhausting. Really heavy chemical smell that you don't notice inside the home. Laundry, candles, etc.
Sigarms
Super Member
Energy usage isn't generally determined by the electric used during run time, but by AMPS used on start up and how many times it cycles.
There is no perfect solution IMO to home comfort per money vs comfort. Sooner or later, you're robbing Peter to pay Paul.
Personally, knowing what I know, I would never build a house too tight per a "vacuum seal".
To make is simple, there is a reason IMO why we have more kids with ADHD than ever before (per what we eat in food IMO). The same can be said for trying to build the perfect home IMO and correlating side effects.
If you're house needs a ERV, loosen it up... Keep in mind, I sell ERV's as well LMAO
There is no perfect solution IMO to home comfort per money vs comfort. Sooner or later, you're robbing Peter to pay Paul.
Personally, knowing what I know, I would never build a house too tight per a "vacuum seal".
To make is simple, there is a reason IMO why we have more kids with ADHD than ever before (per what we eat in food IMO). The same can be said for trying to build the perfect home IMO and correlating side effects.
If you're house needs a ERV, loosen it up... Keep in mind, I sell ERV's as well LMAO
Sorry but I completely disagree. Why bring fresh air into your home through dusty attic space, walls, etc when you can use an ERV to bring clean fresh & filtered air direct to the rooms in your home. You can control exactly how much air you bring in and direct to every room in the home? The energy used from an ERV is negligible. Also how are you going to build your home to be the correct amount of "loose".
Sigarms
Super Member
You missed my point.
If you have a house so air tight you should bring fresh air into your home via an ERV.
My point is that house shouldn't be that air tight where you HAVE to have an ERV.
That said, to each their own.
I get it. You want an ERV, I'll sell the contractor an ERV, no worries. Just saying I wouldn't want a house so tight where I'd need one for my own home. H E double tooth picks... I've had more dogs than fingers on both hands in my own home LMFAO
New construction fresh air, 4" fart vent into the bathroom LOL
I guess I still don't get it. A tight home with a properly setup ERV is going to have better air quality than a loose home and will be more comfortable. Will also use less energy overall heating and cooling. You still have to factor in the cost to build to that spec vs energy savings as I've seen people over do it to the point that the savings will not be recouped for 30 years.
Sigarms
Super Member
My home is "kind of" loose. I can keep my indoor temperature at 78 during the summer and it can be 77 outside and it feels cooler inside than it does outside when it's hotter in the home than outside. Can you make the same claim with your airtight home?
Homes being tight have gotten to be ridiculous. It's not the temperature that makes you feel comfortable, but the humidity level.
With dogs, cats and kids inside the home, air quality is a state of mind. The tighter the home per air seal, the worse off you are with more animals and kids IMO.
FYI, in light commercial applications, we use mixing boxes with split system air handlers all the time when the build requires it. Perfer that set up over ERV's.
And this is much easier to control with a tight home and proper humidity controls.
Your statement is correct with a tight home and no ERV. Incorrect with a tight home and ERV.
I'm not sure to be honest. I set the temp and humidity where it's comfortable for us and pretty much leave it there until fall. I guess if I wanted to feel a draft to make me feel cooler inside I would turn on a fan.
On a side note we use to have 2 english mastiffs as inside dogs in our old home. Diesel was 215 lbs so I do know a little bit about poor indoor air quality. He could clear the entire house. lol.
