Savvv - how will you be air sealing and insulating the attic?

Posted By FBBP on 28 Oct 2015 10:24 AM
Savvv - how will you be air sealing and insulating the attic?

Not exactly sure. My builder has an insulation sub that will come in and spray foam all the top plates where piping and wiring penetrates into attic space. I know there will be baffles installed as well.

Savvv - I have used the unico unit and am reasonably happy with it although I think the component parts are somewhat overpriced. I have a two storey plus basement, with the unit in the basement. All ducts where sized for even distribution and we checked air flow at each outlet to make sure they were balanced. We have one branch running in the attic to feed eight ceiling outlets. Everything is sealed and tested. All pipes wrapped with insulation. No component has less then 4" of cellulose over it and most are buried under 8-10".
In spite of this we still had convectional draw between outlets on the second floor. That is when the unit is off, warm air would rise into some of the outlets and then cool in the attic space, returning as a cold draft from other outlets. This is all happening on the supply side. I had to go back up into the attic and push what ever slinkys I could down against the vapour barrier and in a few areas I had to build cardboard boxes around the pipes and top up the insulation. That stopped the convection caused by cooling but I would never again put ANY hvac components above the vapour barrier.
Do you have easy accesses to the attic to change the filter on the unit? Will you be using glycol in the hydronic system?

Interesting. I will have to be mindful of that when we start running it. I bought my Unico with the ECM motor so I MAY decide to leave it running continuously on low speed to keep air circulating through the house. It'll depend on comfort levels with the radiant on by itself vs having the fan running too. Then, if the house calls for heat, or in the summer when it calls for A/C, it can ramp the fan speed up to deliver the BTU's.

I have what used to be a linen closet designated as an attic ladder access closet to get up into the attic and the platform the the unit is on will be wide open. The heating system will have a 10% glycol mix. Since the Unico hot water coil won't be used majority of the time, my new plan with the heating diagram is to install a cheap thermostat in the attic and set it to near freezing. Once temps drop that low, the circulator pump for this coil will turn on. I'm buying a Johnson Controls 3-way on/off valve and it will normally be closed to the boiler side, so essentially I'll have a coil circulation loop to keep water moving through the coil when temps get low. Then, if my Nest thermostat calls for heat because the radiant isn't energized or there's a big temp swing, the 3-way valve will open and allow boiler hot water up into the coil.

Maybe spend the money to turn the truss braces into walls, frame up the two ends and make an insulated room around the Unico, essentially moving it into the house envelope?

Posted By FBBP on 29 Oct 2015 09:50 AM
Maybe spend the money to turn the truss braces into walls, frame up the two ends and make an insulated room around the Unico, essentially moving it into the house envelope?

I had definitely given this some thought. The part that is tough is all the penetrations through these walls for Unico ducting, plumbing vents, etc that are already installed. Might be more of a project for later on if there's some concern about the system.

Posted an update this morning with some siding and insulation shown. Check it out and have a happy Thanksgiving!

a recent home where we did the entire house including the stair treads with wood looking porcelain plank

That tile install looks great! Amazing what they've done with tile these days and the looks you can achieve.

Just posted a HUGE update for the holidays. Enjoy and see you next year!

Just posted a new update showing off the boiler room downstairs. Check it!

The house look great.  I worry about the number holes in your floor joist.

I see your are using wood floors.  What wood did you find that would go over a radiant floor?  We are looking at building with radiant later this year and would like to have wood floors over radiant floors.

Posted By gwiz on 10 Feb 2016 01:30 PM
The house look great.  I worry about the number holes in your floor joist.

Thank you. I'm not too worried about it myself. The radiant holes are 3/4" if memory serves me correctly, and the manufacturer would recommend 1-1/2" from edge to edge. I'm on 2" centers, so 1-1/4" edge to edge. Not worried about the 1/4" difference on holes this small.

Posted By gwiz on 11 Feb 2016 10:24 AM
I see your are using wood floors.  What wood did you find that would go over a radiant floor?  We are looking at building with radiant later this year and would like to have wood floors over radiant floors.

It's technically bamboo, but same family of install method. You can install most other woods over radiant as well, key is maintaining a proper temperature. My installation method puts the tubing below the subfloor, so as long as the installer doesn't use 4" long nails, we're ok. Another more expensive method would be putting insulated aluminum panels down on top that have grooves in them for the tubing, and then the hardwood goes over this. Yet another method would be beefing up your joist system, doubling up your bottom plates for all the walls, securing the tubing to the floor and pouring 1-1/2" of concrete on top. This will get you the biggest thermal mass for radiant floor, but I have heard of the concrete cracking on some builders. Really comes down to the contractor doing the pour correctly.

Hope everyone had a safe St. Patty's Day. Posted a new update earlier today. Lots more to see from an aesthetic point this time!

...pouring 1-1/2" of concrete on top. This will get you the biggest thermal mass for radiant floor...

Which is a negative, not a positive in an active thermal radiator.

Posted By jonr on 20 Mar 2016 08:58 AM

...pouring 1-1/2" of concrete on top. This will get you the biggest thermal mass for radiant floor...

Which is a negative, not a positive in an active thermal radiator.

Care to elaborate? Without any detail, I'm guessing your reasoning is that once the mass of concrete is up to temperature with hot water flowing through it, there's no "shutting off" the heat until that mass gives off its heat.

If this is where you're going, I don't know that this is STILL a problem today. My boiler knows the difference between slab heating curves and fan coil unit heating curves. Also, my basement loop is run off of a 3-way mixing valve and controller that is all tied back to the boiler controls. Rather than dump 100% boiler supply temperature into the slab, it will mix with return and keep the pump running for quite some time. So long as we have flow we can change water temperatures to keep the slab from overheating, and thus overheating the space.

With these on our side, having all that concrete throughout the house will allow the boiler to run at a lower temperature throughout the season since most of the temperature of the water makes it into the concrete. So long as you are mixing the return continuously you'll have better control of your space.

Got around to taking pictures yesterday and getting an update posted sooner than later. Check it out!

Looking nice for sure.

A couple of questions.  How much insulation do you have in the ceiling?  How are you keeping the unico system warm during the winter months?

How much pex did you run per square ft on your first floor.  Looking at doing something similar but would like to get an rough estimate of how much pex it will take.

I also see a lot of extra boxes inset in your walls.  In the laundry room and kitchen.  Can you explain them?

Regards

Posted By gwiz on 05 Apr 2016 09:37 AM
Looking nice for sure.

A couple of questions.  How much insulation do you have in the ceiling?  How are you keeping the unico system warm during the winter months?

How much pex did you run per square ft on your first floor.  Looking at doing something similar but would like to get an rough estimate of how much pex it will take.

I also see a lot of extra boxes inset in your walls.  In the laundry room and kitchen.  Can you explain them?

Regards

Thanks!

Our attic has R-40 cellulose. We put sound insulation in the ceiling of the family room to keep noise levels lower migrating up into the bedroom above. The unico system is fully insulated, and needs not kept warm during the winter. The only thing to be concerned with is the condensate trap off the unit. They advise pouring some antifreeze in the trap before it gets too cold. The unit is internally insulated with thick black dense foam, and then all of the ductwork is insulated with fiberglass.

First floor of our house is about 1200sqft, and we used about 2000 lineal feet of tubing underneath it. The second floor is 1300sqft and took 2800 lineal feet. The reason for most of the difference is the rise from the basement for each circuit to get to the zone more than likely. Probably 15-20% of the runs were just distribution to the zone.

Most are electrical outlets but the ones near the floor or the ones that appear to have valves inside are for water hook up. Rather than have copper stub ells coming out of the walls, and then having to cut them and solder or compression on angle stop valves, these boxes mounted in the walls with connections on the bottom and it provides a cleaner look and easier to install everything. The flexible lines will connect to these as the valve is inside the box.

I know it's been quite awhile but we are moved in and I've got an update posted!