Keeping my sunroom warmer (making interior storm windows)

[AntiochOG]

I'm planning on building some of these interior storm windows soon too. I'm just trying to figure out what kind of film to buy and where to get it.

[TimJFowler]

Originally Posted by Daox

I'm kind of leaning toward the frame with film on it. Mainly this is due to the higher r value it will provide. I'd like to get as much as possible.

Guy Marsden - insulating windows

I was all set to criticize this plan but I checked out the link and it's a fine idea. Unfortunately, I think the diagram is a bit misleading.

Guy placed his interior storm windows snug against the window frames, not out against the wall surrounding the window opening. Placing the interior storm window away from the window would allow a convective air loop which could negate much of the benefit. Placing the window film close to the window reduces the possibility of air movement within the gap.

So, these interior storm windows could work quite well assuming they are well sealed and set close to the window.

FWIW,
Tim

[Daox]

Yeah, I agree the picture is a bit misleading. However, the basis of adding two extra air pockets is what I'm after. Now, I just have to find a clever way to get it to stay in place in my window sill. The screens are held in place with pins that go in the frame. I was hoping to reuse them.

[gasstingy]

I like the idea of these inexpensive home built window shades I looked at over on builditsolar's website.

Doug's Thermal Shade Design

It's something I plan to try for the garage / workshop project.

[Daox]

I did some measurements last night. At around 4:00 pm my heat turns on to warm up the house for when we come home. The heat is set to 68F / 20C and warms up the living room nicely. However, there are no vents into the sunroom which only makes the problem worse. I should note, I do have hydronically heated floors in the sunroom which I love to use. However, it runs off my horribly inefficient water heater, so I try not to use it much. Anyway, I took some temperature measurements last night. The red dot represents the furnace thermostat location. The green and blue dots are other thermometers. Here are the observed temperatures:

Outside ambient was probably around 25F / -4C
Red - 68F / 20C
Green - 65F / 18C
Blue - 60F / 15.5C

Pretty huge swing there! The blue dot is on an end table next to the couch, so its kind of chilly there hanging out at night.

[RobertSmalls]

Your solarium looks like a huge energy sink in the winter. The greenest thing to do, of course, would be to close it off with heavy curtains, doors, and/or foam for the winter, and drain the hydronic system so the pipes don't freeze. It's a large number of square feet that mostly duplicate the functionality of the living room and porch. But perhaps there is some sort of happy middle ground between making it seasonal and the status quo.

I scored some secondhand thermal curtains, hung them in my living room (with north-facing windows), and found that they trap heat OUT when it's sunny and 40°F out, but they do good work at night.

Having as many windows as you do, you could build a couple interior storm windows, hang a couple thermal curtains, and leave a few in the control group. Take measurements near the windows and see what works best.

Can you move the couch to where the green dot is?

[Daox]

Well, the living room is really now an office, and the sunroom is our living room. We keep lots of plants there over the winter, so we can't completely close it up for the winter. So, we'll have to find some compromise. I agree it is a huge heat sink at night. However, it also does harvest a fair amount of heat during the day and in general is just a great room to hang out in.

The couch can't be moved to an inner wall due to the fact that there is no real place to put the tv then. It would be blocking the windows which I don't like the idea of.

We'll see how the inner storms do though. I'm planning on swinging by the home improvement store on my way home from work today.

[Daox]

I picked up supplies on the way home today and started working on the interior storm windows. Here is what I got:

13 - 1x4x8 pine boards
2 - 10 window insulation kits
1 - can of stain to match the window sills
1 - 90 degree clamp to assist in assembly

The total for all of this came to $50 and is almost everything needed to make the storm windows. The three things missing are screws, packing tape, and stick on foam. I had some screws I thought would work, but found out they're too big and split the wood. I have packing tape. The foam I couldn't get at the local store. The instructions specifically say to get 1/2" x 1/2" open cell foam and I could only find closed cell foam.




So, I started cutting up the boards. One board is enough for one window.



Here they are all cut up. I couldn't start assembling because I still need to find some smaller diameter screws.

[Daox]

No picture updates as of right now. On Sunday I sanded down all of the long lengths of 1x2. I want these things to last a long time and look good, so I'm taking a bit more time. I still have to figure out exactly what stain I'll be using on them to match the existing window sill.

I also did some quick calculations on builditsolar's cost saving calculator for insulation. I'll be covering roughly 135 square feet of window with these interior storms. A rough guess is it'll tripple the insulation value from ~R2 to ~R6. Plugging those numbers in shows I'll be saving around $90 in my first year of usage. That more than pays for all the materials so far. I still have to find some 1/2" x 1/2" open cell foam.

[PaleMelanesian]

Did you try pre-drilling for the screws? I find that stops most splitting problems. Use a bit that matches the shank on the screws, so only the threads are engaging the wood.

Countersunk heads can still make trouble, though. I use drywall screws for most projects and that's a major issue with them.