Nearing the end of major remodeling

Elcam84 · 09-03-21, 05:52 PM

Well I'm getting near the end of all the work I need to do in the attic. I had to move walls run wire run vent pipes etc etc. And It's finally coming closer to an end. Well at least close enough that I can start looking forward to insulating the attic properly.

I didn't want to insulate the attic then fight all that insulation to get work done so the HVAC will end up being oversized once everything is done. With the virtually no insulation up there (4" of 1960 rock wool) the manual J showed I needed a 3.5 ton unit and whatever the furnace size ended up as(AC size is the primary factor here)

Now once I am able to get a nice thick layer of insulation up there I will be down to a 2.5 ton unit. I can't wait for a more comfortable house and a quieter AC unit. Upflow gas heat units are not the quietest things around since there is nothing between the blower and the return grills to stop the sound.

I will be either buying 30 bags of fiberglass blow in or 100 bags of cellulose. Unfortunately we have no Menards here so insulation is more expensive here and it's cheaper to buy more than I need than exactly what I need. And I can just pile the crap out of it...

The plan is to take the old unit and put it in the shop. It's an insulated 20x40 but will be 20x58 soon. Right now a 2 ton unit isn't enough to cool the shop when it's over 95*. Unfortunately I don't have a gas line out there yet so not sure what I will do for that yet. AC is more important than heating in the shop.

JRMichler · 09-06-21, 12:40 PM

Did you seal all penetrations to the attic before adding insulation? If not, sealing attic air leaks is more important than most people realize.

There is (almost) no such thing as too much insulation in an attic. My previous house had R60 insulation in the attic, and it really made a difference when we had several days of 100+ deg F temperatures. So I had the attic of our current house insulated to R96.

Elcam84 · 09-06-21, 01:15 PM

I haven't done the insulation yet as it's still summer here until october.... All the usual has been done. in fact the only wiring penetrations into the attic are for light switches as all the outlet wiring is run under the house and those are a pain to get to as well. Some parts you just can't get to as the roof is in the way...

I do find that using manual J calcs tend to result in a slightly undersized unit here as the published man J outside temps for here are not accurate for this area cs real historic data. Unfortunately not everyone can live at the airport where it's cooler in the summer and warmer in the winter. (chamber of commerce adjusted temps)
But I don't mind if it is a hare small as I plan to put in a minisplit in the kitchen so we are able to cook in the summer and I'd like a super tiny minisplit for the office because both of those areas have issues with conventional cooling systems in the summer here.
AC systems just can't keep up with the extra heat produced in the kitchen in the summer when it's 100*+ . As for the office the computer in there puts out as much heat as a space heater. Multipule monitors energy socking big video card etc and that is running full last for 12+ hrs a day.
Either of those end up making the ac unit run more and overcool some areas and undercool those areas.

I'm still thinking if I want to put the house unit in the shop. Since it's under 10 I can resell it for a decent amount. Then I may end up going with two minisplits in the shop as 2 are cheaper than a two head unit and redundancy is key as well not to mention far more efficient than a conventional system. Then when I add onto the shop that area will be a paint booth and get it's own unit as well.

09-03-21, 05:52 PM	#1
Elcam84 Apprentice EcoRenovator Join Date: Jun 2013 Location: TX Posts: 275 Thanks: 2 Thanked 31 Times in 24 Posts	Nearing the end of major remodeling Well I'm getting near the end of all the work I need to do in the attic. I had to move walls run wire run vent pipes etc etc. And It's finally coming closer to an end. Well at least close enough that I can start looking forward to insulating the attic properly. I didn't want to insulate the attic then fight all that insulation to get work done so the HVAC will end up being oversized once everything is done. With the virtually no insulation up there (4" of 1960 rock wool) the manual J showed I needed a 3.5 ton unit and whatever the furnace size ended up as(AC size is the primary factor here) Now once I am able to get a nice thick layer of insulation up there I will be down to a 2.5 ton unit. I can't wait for a more comfortable house and a quieter AC unit. Upflow gas heat units are not the quietest things around since there is nothing between the blower and the return grills to stop the sound. I will be either buying 30 bags of fiberglass blow in or 100 bags of cellulose. Unfortunately we have no Menards here so insulation is more expensive here and it's cheaper to buy more than I need than exactly what I need. And I can just pile the crap out of it... The plan is to take the old unit and put it in the shop. It's an insulated 20x40 but will be 20x58 soon. Right now a 2 ton unit isn't enough to cool the shop when it's over 95*. Unfortunately I don't have a gas line out there yet so not sure what I will do for that yet. AC is more important than heating in the shop.

09-06-21, 12:40 PM	#2
JRMichler Apprentice EcoRenovator Join Date: Apr 2012 Location: Phillips, WI Posts: 109 Thanks: 10 Thanked 30 Times in 25 Posts	Did you seal all penetrations to the attic before adding insulation? If not, sealing attic air leaks is more important than most people realize. There is (almost) no such thing as too much insulation in an attic. My previous house had R60 insulation in the attic, and it really made a difference when we had several days of 100+ deg F temperatures. So I had the attic of our current house insulated to R96.

09-06-21, 01:15 PM	#3
Elcam84 Apprentice EcoRenovator Join Date: Jun 2013 Location: TX Posts: 275 Thanks: 2 Thanked 31 Times in 24 Posts	I haven't done the insulation yet as it's still summer here until october.... All the usual has been done. in fact the only wiring penetrations into the attic are for light switches as all the outlet wiring is run under the house and those are a pain to get to as well. Some parts you just can't get to as the roof is in the way... I do find that using manual J calcs tend to result in a slightly undersized unit here as the published man J outside temps for here are not accurate for this area cs real historic data. Unfortunately not everyone can live at the airport where it's cooler in the summer and warmer in the winter. (chamber of commerce adjusted temps) But I don't mind if it is a hare small as I plan to put in a minisplit in the kitchen so we are able to cook in the summer and I'd like a super tiny minisplit for the office because both of those areas have issues with conventional cooling systems in the summer here. AC systems just can't keep up with the extra heat produced in the kitchen in the summer when it's 100*+ . As for the office the computer in there puts out as much heat as a space heater. Multipule monitors energy socking big video card etc and that is running full last for 12+ hrs a day. Either of those end up making the ac unit run more and overcool some areas and undercool those areas. I'm still thinking if I want to put the house unit in the shop. Since it's under 10 I can resell it for a decent amount. Then I may end up going with two minisplits in the shop as 2 are cheaper than a two head unit and redundancy is key as well not to mention far more efficient than a conventional system. Then when I add onto the shop that area will be a paint booth and get it's own unit as well.