Installed Radiant Barrier, thinking of solar vents now? (Plano, Allen: how much, house)

[labor omnia vincit sxi]

I installed radiant barrier foils in my roof last May 2010 (myself) but I noticed that it didn't make any 'significant' difference to my monthly bill. It is a 2 storey house built in 2000 with AC controls on each level. I have passive ventilation in the roof. Here are a few of my observations:

• The AC controls are located in the game room upstairs which has only 1 cooling vent. During the hottest time of the day, the AC unit struggles to cool the game room down to 82F with just that 1 cool vent (12 ft away from the control). So the AC unit runs the whole time until it 'overheats' and then cuts off to cool down. And then it repeats struggling to cool the room again. (The master bedroom next to the game room has 2 vents and it gets cold in the room at the same time)

• the afternoon and evening path of the sun has direct access to the game room, adding more heat through the walls (and the windows)
  

• my AC unit might be underpowered or not as efficient as the newer models.
  

• I did not increase my R value back again after 'flattening' my insulation in the course of tacking the foil barrier

The barriers does work, cools the attic by 10 - 15F but heat still permeates down significantly (probably due to the flattened insulation). Temp. reads about 110 to 119F under the foil barrier (a remote thermostat bought from Walmart), while the game room reaches about 95F if the AC doesn't come on. With the AC on, it cannot get below 87F. So throughout the remaining months (July - Sept) I tried to compensate by keeping the 1st floor ~77F, (it did help a little but not enough) and set the game room to 88/89F so that the AC gets a chance to rest.

Last December, I've blew in an additional 9 bales of cellulose to compensate the lowered R insulation value. Now I am thinking of adding a couple of Solar Ventilators to help move the air in the attic out but I want to be able to turn it off in the winter months, so I am thinking of rigging the connection between the panels and fan to add a switch that I can easily get access to. Costco has the solar vents for $300 a piece.

I'm looking for a roofer to put up the solar ventilator and would like to ask if there are any recommendations or additional opinions


Thanks



Labor Omnia Vincit

[skids929]

I can't for the life of me understand why they don't use ridge vent and a continuous soffit vent in Texas. Anyone?

Have an HVAC guy come out and balance the system first. Are there any dampers you can adjust in each room? Not the dambers in the ceiling, I mean the ones at the trunk line. If not have a supply added in the game room then balance from there. Just don't make that room too cool and get the opposite effect in other rooms, the key is balance.

I bet those air hawks will help alot, it's the same theory as Ridge and Soffit vent really. If you had ridge and continuous soffit and the air hawks in theory you could keep that roof temp alot closer to the actual ambient temp outdoors, which is the goal really.

Did you put the radiant on the back of the rafters? And when you say solar ventilator do you mean with solar panels? Does hail have the potential to wreck the solar panel?

[tyanger]

I agree you should look into adding vent(s) and dampers as skids929 suggests.

Depending on the location and orientation of the windows to the game room consider solar screens for those windows.

Look at the location of the attic access panel/ladder and see if that could be contributing to your problem. I had a problem in an upstairs jack-n-jill bathroom and the adjoining bedrooms getting too hot for a variety of reasons, but the attic access in that bathroom was a big factor. I was able to improve things with additional supply lines and vents with dampers as well as an insulated and reflective attic door cover that goes in the attic over the folded up stairs. Its like a rectangular box that zips open and closed.

An inexpensive infrared thermometer might also help you narrow down problem areas that might not be that obvious.

[lh_newbie]

Adding venting toward the "top" of your roof will require having venting toward the "bottom" of your roof - hence the above mentioned continuous soffit vents. Make sure both are adequate to remove the hot air from your attic space.

It definitely sounds that your HVAC system is not balanced properly if you have one at a very different temp than another in the same zone. You want to get that fixed first and foremost - you'll want an HVAC professional to evaluate the size of ductwork and # of vents in each room. To me, one vent in a game room and two vents in a bedroom sounds a bit off base. While they are there, they should evaluate your current system to make sure it's operating efficiently, as a system should not run full bore until it overloads and then shuts down.

No amount of insulation or foil will make up for an HVAC system that has incorrect supply/return lines or a system that isn't running properly. I highly recommend getting a professional in to evaluate your current system.

Brian

[loves2read]

you'll want an HVAC professional to evaluate the size of ductwork and # of vents in each room.
basically Brian means get someone out there who knows HVAC to check your system--
most homes that are tract built have awful HVAC designs because they take none of the individual aspects of the house into consideration
AND many times they are always done to minimum specs which means the system is undersized, the arrangement of vent/run is done as cheaply as possible and the ventilation in the roof/attic is usually not going to help anything
often times the guys doing the install do not open up the vents on the underside of the eaves so that they are even pulling in any air--

I can't for the life of me understand why they don't use ridge vent and a continuous soffit vent in Texas. Anyone?
builders built to code--that is not "code" or it was not in most towns a few years ago--eventhough that seems like it should be common sense construction in area of country with almost 2/3 heating days and 1/3 cooling ones...

[labor omnia vincit sxi]

Thanks for your opinions.

Originally Posted by skids929

Have an HVAC guy come out and balance the system first. Are there any dampers you can adjust in each room? Not the dambers in the ceiling, I mean the ones at the trunk line. If not have a supply added in the game room then balance from there. Just don't make that room too cool and get the opposite effect in other rooms, the key is balance.

I do not notice any dampers in the ducts in the attic, so I'm going to say no dampers. My passive vents are those plastic type, not the air hawks and no I do not have continuous soffit. There were styrofoam type of gutters in the attic, my guess is that it acts like a drain for the soffit to the top of the attic.

I stapled the foils to the rafters, it was MAJOR pain as the ceiling of my 2nd floor is not uniformly flat like those seen in you tube. My ceiling is "multi-level"; (the game room ceiling is higher than those in the bedroom), and the most annoying part is that they all tapers in a slope at the sides of the room. Which means that in the attic, there all sorts of angles and slopes with plenty of very hard to access horizons. Getting access to the edges to staple the foils required a contortionist . Luckily I had left over laminate boards from my old house and I used that to lie between the rafters and practically surf my way around ft by ft.

Well the whole idea of me doing the foil myself was to save me $$, but I do understand the argument of getting an HVAC guy for a professional opinion to balance the area. That doesn't prevent me from feeling deflated that after all the hardwork put in, it didn't make a dent in saving energy bill.

As for hail damage to the solar panel of the ventilators, I want to say that they should be able to withstand the impact but can't prove it.

And I just realized that after viewing some of the youtube DIY vent install, it is going to be very difficult to gauge between the rafters (to place the vents) as the foils are covering all of them I might have to tear down those foils??

*sigh*

[adixyz]

A radiant barrier (foil or spray) helps reduce electricity only to the extent of 10%. The other major items to reduce energy are insulation & ventilation assuming you have no windows/door leaks.
Most Builders normally follow ICC Code (1/150 rule) but this is the minimum and not sufficient for Texas heat. It appears to me that you have either less air intake or the hot air in the attic is not going out.
Try to find the out your Net Free area (of the intake + outlet vents). The general rule of thumb of what works is 10 Sq.ft of Net free area per 1000 sq.ft of attic. Accordingly increase the number of inlet vents in appropriate locations. Note that building code won't let you add inlet vents above kitchen or in certain places. So verify the code for the locations. You also need at least 10 air changes/ Hr. Find out the Attic volume and replace passive outlet vents with Whirly's or Attic Fan/ Solar Fan.

[DaveG99]

Im in the roofing business and I prefer ridge vents to the other types. They look great and do a great job of venting the attic. But it depends on the design of the home. Some homes dont have enough ridge.

[labor omnia vincit sxi]

Thanks ADI and Dave.
I'm at Allen/Plano, and have made an appt with Philips roofing guys to come out and take a look on Monday.
I don't believe I have ridge vents at all.. would that add coldness to the attic in the winter because of it's design?

I was thinking of a solar vent earlier as I wanted it to be self sufficient, and to be able to turn it off during the winter. I saw a unit in You tube that would shut off if the temp is below 65F, that's cool.
U.S. Sunlight Corp | Solar Powered Attic Fans

But from the collective comments so far, it sounds as though having a continuous Soffit, ridge vents and sky Hawks should be sufficient in to move the air in the attic.

[skids929]

Originally Posted by DaveG99

Im in the roofing business and I prefer ridge vents to the other types. They look great and do a great job of venting the attic. But it depends on the design of the home. Some homes dont have enough ridge.

Great point here, which may be the reason alot of the newer homes don't have them since they are all hips and valleys. I still think the system could help though and then you would minimize all those ugly round vents at the top of the roof too.

Labor- so does stapling the foil have any adverse effects? Like creating an intense heat pocket in the rafter bays? I would think it would deflect that heat right back out at the shingles, maybe shorten the life of the roof?

Also, I look into those solar power air ventilators for my brother in law in Southlake. The only thing in front of the solar panel is tempered glass, which if you have ever seen break you know why a golf ball sized piece of hail is a big risk. Tempered glass is a disaster when it shatters and it will destroy a $300 item. You could probably retrofit with Plexi though and that would deflect, but still seems like alot of trouble.

Look under the insulation right where it the supply lines connect to the trunk line to see if the dampers are there, sometimes they are hidden. And there aren't any and that home were built in the last 10 years or so, then shame on that builder. Either way, easy install, very easy. I would still want a HVAC guy to come out with that air-balancing tool so you make sure you are getting the right push into each room. Once you dial in an HVAC system you would surprised how much comfort it can add.