Ventilation

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Old 01-20-13, 10:15 AM
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Ventilation

I am looking for better ventilation in my house. Everything I have seen for ventilating a house are additions to ductwork. There is none in my house we have baseboard electric and no central ac. Are there any other options to ventilating my house besides adding ductwork.
 
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Old 01-20-13, 11:22 AM
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The most economical way would be to use a heat recovery ventilator.

This is a device that exhausts air and replaces it with air that is warmed or cooled by the outgoing stream.
There are different ways to configure it.
Some will modify the kitchen and bathroom exhaust hookups to have the HRV as the exhaust fan then connect a grill in the hallway for the outdoor air to enter the house.

In cold climates if you are connecting an HRV unit to a grill in the house you would need to purchase one that is able to warm up the air supply.

A less expensive way is to operate your bathroom exhaust 24/7.
Doing so will exhaust stale air and allow it to be replaced through leaks and when the doors are opened.
There is a slight cost in doing so but there is no way, even with an HRV to exchange air for free.
 
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Old 01-20-13, 11:38 AM
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Thanks for the reply. Not looking for a free way but just a way to help ventilate the air without putting in duct work. I will have to look into the HRV. Do you recommend any websites for me to look at? Or suggest any products?
 
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Old 01-20-13, 11:46 AM
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Hi larglin,
Can I ask why you feel you need more fresh air? Most homes already leak too much. It requires extensive air sealing to even get down to a threshold where one should consider adding ventilation. New homes can be sealed as they are built and builders would already have installed a HRV or ERV.

Are you experiencing condensation on your windows? Have you measured your inside relative humidity (RH). Do you have any moisture issues prompting the need for ventilation?

Do you have a basement?

Bud
 

Last edited by Bud9051; 01-20-13 at 11:47 AM. Reason: additional question
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Old 01-20-13, 11:56 AM
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Are there any other options to ventilating my house besides adding ductwork.
Yes....open the windows

With electric baseboard heat you need to conserve every BTU your hard earned money is paying for.
 
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Old 01-21-13, 06:07 AM
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Bud

Yes we have seen condensation on our windows. I have been opening the windows for about a half hour each day and it seems to be helping but if I forget to close them the heat is constantly running. The upper floor of the house seems to be the most humid, we measured the temp in our spare rooms at 60 degrees F and the humidity ranged from 57-63%. Now that I opened the windows it ranges from 47-55.

Yes we do have a basement and have been running a dehumidifier in the basement for over a year now and it has gotten to the point where the dehumidifier rarely turns on now in the basement.
 
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Old 01-21-13, 07:45 AM
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60° and 60% RH gives you a dew point of 46°, pretty hard to keep the windows above that. At 50% RH it only drops to 41°, still requires some good windows to avoid moisture. Here's the calculator if you want to play.
Temperature, Dewpoint, and Relative Humidity Calculator

I agree ventilation is a solution, but I always hate to treat the symptom if I can cure the cause. So why all of the moisture? Have you or someone gone radical with air sealing? Not all dehumidifiers perform well in cooler temperatures. You might want to take some RH reading down there to confirm that the the basement isn't still your source of moisture. Over 50% of the air circulating through your home comes from the basement.

Standard moisture reduction methods include, timers on your bath fans to keep them running for 20+ minutes after showers. Low flow shower heads. Addressing the moisture in the basement if that turns out to be a source. A gazillion house plants. Dryer vented into the conditioned space, maybe blocked or disconnected. Drying cloths inside. Storing firewood inside. And other surprises related to moisture.

You can take RH reading in different areas of the house and basement, convert them to dew point and look for the highest, that may point you to the source of the moisture.

PS an air exchange system with filters is actually not a bad idea, just no need for it to be working against something that can be fixed. Radon should be tested as well in a tight home.

Bud
 
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Old 01-21-13, 02:29 PM
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Bud

I will take some readings in the basement. We don’t have any houseplants and I have checked the dryer vent and it looks to be functioning properly and is clean.

The Air exchange system that you mentioned does that require ductwork? We had the radon tested when we had the house inspected and was about average. He said there were a few hours that it ran alittle above average but wasn't considered high.
 
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Old 01-21-13, 03:53 PM
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I believe there are air exchange systems that can be installed as stand alone units. From there it would depend upon how ell your home is connected. If doors are closed, fresh air in one area may not help in others, but that's obvious.

In reality, the energy recovered by having the exhaust air exchange it's heat with the incoming air is not a lot. It's more of a comfort issue. Other methods are to run a bath exhaust fan for a couple hours a day. The air that exits will be replaced by infiltration through existing leaks.

Search HRV (heat recovery ventilators). They do have window units from a quick search I did. The other application of this process is an ERV (energy recovery ventilator) which recovers some of the moisture as well. Which you do not want.

Run a bath fan for awhile or crack open a window where it isn't uncomfortable and see how the humidity responds. Hold off on buying a HRV until you have determined if your issue is too much moisture or too tighe of a house.

PS how old is the house and to your knowledge, were special efforts used to make it super tight. I know of one that wrapped the house in plastic before the siding. Tight, but a total disaster.

Bud

Bud
 
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Old 01-21-13, 04:25 PM
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Most homes require 60 to 80 cfm of fresh air when occupied! Another option is a ventilating dehumidifier like therma stor.
 
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Old 01-22-13, 06:21 AM
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Bud

The house is an older house i think like 60-70 years old but it was gutted and remodeled and from speaking with the contractor that did the remodel it seemed as though he made sure the house was tight. I think it is a pretty tight house because in the summer when we run the air conditioners the cool air stays in the house for quite a long time and in our precious place the air conditioner would run more often because the cooler air would escape trhough leaks in the house.

I have noticed that when we crack a window in the spare rooms the humidity does drop but then the heat is constantly running so you can say I am throwing my money out the window.
 
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Old 01-22-13, 10:43 AM
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Indications are looking at a tight house. Insulation and air sealing are two different beasts, and both can allow heat to escape or heat to enter during warm weather. Some RH readings from the basement would confirm whether it is a source or not. Use temperature down there and the RH to calculate the dew point. Then use that dew point and the temperature upstairs to calculate the RH of the basement air once it moves up and is warmed to house temperatures. If the resulting RH is lower that the house reading, the basement is not the source. Easier to do than describe. Sorry for the long.

Bud
 
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Old 01-22-13, 01:49 PM
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Bud

Would you be able to let me know what HRV Window Units you found? i tried to do a search for them but had no luck. Thanks!!
 
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Old 01-22-13, 04:32 PM
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I knew you were going to ask .
I did some more searching and the concept seems to be talked about but rarely offered. I did find one that will give you an opportunity to compare price and function. I will also include two links for more information than you ever wanted.

It seem the HRV industry has focused on a centralized system, and given the important nature of these units it is worth considering making this a permanent install. If you have an open basement, I don't think a lot of ductwork would be necessary to make it work. Anyway, here are the links:
HRV or ERV? | GreenBuildingAdvisor.com

A New Way to Duct HRVs | GreenBuildingAdvisor.com

Introducing the PuriFresh Energy Recovery Ventilator

Bud
 
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Old 01-22-13, 07:32 PM
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OK I got some readings from the basement. RH was an average of 60% and temp was 48. We are putting heat in the basement.
 
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Old 01-22-13, 08:25 PM
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Temp is way to low for any off the shelf dehumidifier to work well. Even the good models will have at least half there capacity reduced because of the low temps. I'd look into a ventilating dehumidifier for the basement first
 
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Old 01-22-13, 09:06 PM
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Using that calculator, your 60% RH at 48°, once it moves up to your living area at 60° will be 39% RH. When the air warms up, its RH reading goes down. Since that is well below the 57% -63% RH @ 60° you measured it tell us your extra moisture is not coming from the basement. Not to say the basement wouldn't become a contributor if you stopped running the dehumidifier.

If you go the route of an air exchange unit, an HRV, then where you remove the air from and where you direct the incoming air may include the basement, which might eliminate the dehumidifier. I'm not familiar with ventilating dehumidifiers as Airman suggested so I'll need to read a bit.

Have we overlooked any extra sources of moisture, 4 teen daughters taking 1 hr showers, I had two now grown and gone?

Bud
 
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Old 01-23-13, 05:42 AM
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Old 01-23-13, 05:45 AM
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Thanks airman I will look into that.

Bud, it's just me and the wife right now so no excessive long showers. We are having our first child in April so that's why I have been looking to fix this problem.
 
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Old 01-23-13, 08:11 AM
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If you want to confirm how tight the house is to increase your confidence that fresh air is needed and determine how much, the test is called a blower door test and usually done by an energy auditor. If you request just that test it would take less than an hour and not require a report so they should quote a reasonable price.

I haven't given this much thought and maybe airman can give you a better opinion, but if you went with a HRV and installed it in the basement you could pull air from outside and condition it through the exchanger and dump some or all of it into the basement. That would be very dry air. Then pull inside air from the living space that is contributing the most moisture and exhaust it to the outside after the exchanger recovers some of the heat.

Outside air in the winter in PA should be rather dry when warmed up tp house temperatures so you should see your RH go down both in the house and in the basement.

Bud
 
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Old 01-23-13, 08:30 AM
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The HRV will work in the winter by bringing in the dry air. My issue is he is in PA, a green grass state. He has a basement. A dehumidifier would be recommended during no load times and in the summer to remove the extra RH. the HRV is not going to be able to do this. Thats why im going with the deh. The HRV would be a great way to bring in fresh air. If you could do this with a good dehumidifier it would be the best system you could get. Id highly recommend getting the basement temps up to at least 65 that would help the dehumidifier out.
 
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Old 01-23-13, 08:33 AM
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Thanks airman, point well taken. I often forget about the summer conditions.

Bud
 
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Old 01-24-13, 06:18 AM
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Thanks Bud and Airman, I will look into a dehumidifier that also brings in fresh air.

We are looking to put in heat in our basement. We have electric throughout the house but we do have a natural gas hookup that runs through our basement. Is one better than the other as far as helping with RH?
 
 

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