Ventilation in bedrooms with dual glazed windows

Hello
Last year I have replaced the windows in all bedrooms with the dual glazed ones for noise and heat gain/loss issues.
But that introduced the problem with ventilation, with CO2 getting to 1600ppm in the child bedroom over night.
I have not measured in our master bedroom, as we sleep with the doors open to hear the kids.

Any ideas on how can this be fixed? Obviously keeping doors/windows is not very feasible, as it defeats the purpose of having dual glazing done in the first place.

Things I looked at (in no particular order):
1. Small HRV system like this one http://www.fantechhhv.co.nz/pages/product_sub.asp?page=aerofresh
2. Positive input ventilation like http://www.fantechhhv.co.nz/pages/product_sub.asp?page=pivLoft or http://www.fantechhhv.co.nz/pages/product_sub.asp?page=mivAir but it is mainly for heating in winter as don't want to be pushing the hot air inside during summer
3. Heat transfer kits like http://www.fantechhhv.co.nz/pages/product_sub.asp?page=FTPHTK1-3. Not really fresh air, but can be used to push cool air (living room has air con) during summer and warm air (air con or gas fireplace) during winter.
4. Ducted air con - most expensive option
5. HRV whole house - less expensive than ducted air con but still very pricey

All options come at cost of at least $600+ but cannot decide on what is best. If I go cheap, it will be cheap and I may need to re-do it later. Not all windows/doors are sealed, so whole house HRV maybe an overkill as I really only need it at night (and few hours during the day while the kids are asleep)

Anyone has suggestions? At the moment I am inclined to combine option 1 and 3. With an in-wall HRV in the living room near the air con and heat transfer kit from the living room to the 3 bedrooms.

Might like to read this report and first determine if it is actually a problem and secondly what you could do to fix it if it is.

That study just proves that CO2 can rise to over 3000ppm in a room with 2 occupants over night and references 1000ppm as a standard.

Excellent. Now you can justify even the most expensive solution.

Do not understand - if you have nothing to add of value, why bother responding at all? If you do, can you please explain what you meant?

Pardon? So the conclusions and solutions outlined in the study were of no value to you?

The study also says:



Earlier, it described SBS complaints as being "headaches, tiredness, eyes, nose or throat irritation". Have your children been exhibiting similar symptoms? If not, then perhaps the observed CO2 levels of 1600ppm are of no consequence, especially since they are below the 5000ppm average exposure limits set by various agencies, and well below 7000ppm that is at the lower level of the prolonged exposure levels under which "adverse health effects have not been observed". If they have, perhaps there is another cause other than lack of ventilation.

That said, let’s see if anyone else chimes in with a differing view.

sorry, did not want to be rude =) I used the "download pdf" option and did not see the reference you provided. So after seeing your response I though you were a smartass - sorry again.

Now that this is out of the way, I did see the reference to the space station etc etc mentioned elsewhere. But they never did the test to see how it impacts a brain of a child when exposed to the elevated levels of CO2 for prolonged periods. I did see some experiments that people did at schools, correlating lower attention span to higher levels of CO2 (no proper ventilation).
Lower oxygen levels are not always a bad thing (people live longer up high in the mountains) but lower oxygen does not mean higher CO2 levels.
I have spend money on dual glazing and now I feel that I am not having enough fresh air at times, and maybe it makes it harder to wake up in the morning =) Just looking for some advice to deal with it, as changing nothing is what I am doing already

Is that your guess, a casual observation or have you really studied the situation? Honestly, you might be looking for a solution to a problem you don't have. I have no idea what experimentation you have done to come to the conclusions you have, but in the first instance you could trial a period (say a month) with the doors closed and then compare the results to a period with the doors open. It would be a shame to somewhat reverse the benefits you have paid for with the installation of double-glazing because of a hunch.

In terms of the effect on your children’s brain, many children in history have grown up in houses with open fireplaces and less savoury heating systems, and yet we have still had brilliant leaders, scientists and artists despite that exposure. The syndrome we are most likely to suffer today is being "worried well".

Finally, remember that CO2 is generally used as a proxy for air quality, and if there are issues they might be caused by other "pollutant" emanating from materials in the room, so there may be a very simple solution: get rid of them.

I have not specifically studied it, but concerned of my children's health. Will measure CO2 in just a closed bedroom without anyone in it. If it goes up - will have to look for things that cause it.
You are most likely right about "worried well" thing though =)

What about opening up a window slightly during night time?

What is the point of dual glazed windows if you have to open them at night? Summer time - sure. But winter time... Also we got dual glazed windows for noise issues with neighbours as well and keeping them open will not help much.
So for the moment I am doing nothing - keeping windows open when I can.
I just wanted to discuss this, as a lot of people nowadays are installing/retrofitting dual/triple glazed windows but I do not see a topic of ventilation discussed

This is more than fine, in Russia and Scandinavian countries people also have double and tripple glazed windows and still prefer to open small 'fortochka' for the fresh air during MUCH colder winters.

You do not have to open them too wide, just a small opening is more than enough.

Ventilation provides very similar effect.

People in Russia and northern countries with cold winters have central heating. Keeping window open causes energy loses regardless who pays for them. Best option is to have heat recovery ventilation system installed if one can afford it

sergey try this viewtopic.php?p=1782131#p1782131

Yeah, I looked at them and... too expensive. My house is not built to the passive house standards, so using HRV will be an overkill. Ducted AC with HRV inflow (through the wall - around $1000) is what I would go for if I had the money now

I don't think you need air tightness to the level of a passive house but trying to eliminate as much draughts through sealing doors/windows can make a difference. Although you have installed new windows so that should make some difference.

When you are in a house you think you are getting clean air all the time. I was sadly mistaken once I started reading about the role of active ventilation systems.

I agree, but can not agree with the prices we are charged here. A fan and a heat exchanger in a box cannot/should not cost the same or more than the ducted AC. The benefits of clean air are outweighed by the cost. I am trying to solve my issues on a small budget. But if I could stretch it to $10k, I would not spend it just on HRV system alone.

Hmm. You would need to pay for HRV electricity power if you use it, too.

I believe that having even a basic electric heater in a bedroom while having a window slightly open will be more energy efficient and cheaper than HRV even in the short run. Just make sure your bedroom door is well sealed to prevent droughts.

What kind of heating system are you currently using for your home?

PS. I know that some people are using cryptocurrency mining rigs for heating these days - they definitely pay off for their electricity + generate significant extra income You receive 800-1600 W of heating power with one rig So may be consider investing into one of those instead

=) don't think you would be able to sleep next to the crypto mining rig =)
Heating burns oxygen and uses a lot more energy than HRV system does. Don't forget that with open windows comes noise as well. For heating/cooling of the bedrooms I use nothing currently. Just insulation and the temperature of the house.
For pure ventilation purpose I could use a heat transfer kit to drive the air from another part of the house. Most likely be the living room that has an aircon/heater. But to add a bit of fresh air, I would add an in wall HRV like http://www.fantech.com.au/images/Brochures/Aerofresh.pdf - does 60m3/h on high setting but only uses 7W with heat recovery of 80%. I think this is really good in comparison to the heat loss/gain with having a window open

More expensive option would be to add ducted AC and have it drawing air from the area where that in wall HRV unit is, so that fresh air is added to all the rooms