Block off Plate = more heat?

[PlayWithFire]

I’m running a HI300 Hampton Regency insert into a double walled stainless steel liner which was wrapped in 1-2 inches of insulation. There is block off plate on the top of the chimney, but NOT inside the fireplace. When the temp is 20 or below, the insert just can’t keep my 2100 sq/ft house warm enough. If the outside temp is 20, the best I can get the room is 72 with the fire roaring and fan on high. One room away from temp drops to 60.
I’m wondering if stuffing some fiberglass up the masonry flue and adding a block off plate at the inside-top of the fireplace will make a difference.
Has anyone had any before and after experience with a block of plate? Any other thoughts on how to get more heat out of the HI300?
Thanks!

 

[USMC80]

IMO the hampton will not heat 2100 square at those feet regardless of your setup. I just used roxul. But a plate definitely couldn't hurt

 

[USMC80]

Now that I look its only rated for 2000 square and take that with a grain of salt.

 

[NRGarrott]

Can you tell us about your house? Also roxul, which is mineral wool is a better choice for insulating inside your chimney than fiberglass.

The high temperature where you live is 21 degrees today. I wouldn't expect a stove at the upper limit of its rated capacity to heat the house much past 70 when it is only 20 degrees outside.

 

[PlayWithFire]

At 75k btu I was hoping it would do a little better, but I guess that was unrealistic.

The house is a contemporary colonial style. 2x4 walls, attic has R60. build in 1985. chimney is on an outside wall and all the rooms on the first floor are fairly open. I use 3, 7 inch fans to move air around the first floor.

 

[NRGarrott]

Can you slide the insert out, and make a blockoff plate for the bottom of the chimney?

 

[PlayWithFire]

Can you slide the insert out, and make a blockoff plate for the bottom of the chimney?

I can.... it's just a pain since the liner short and will need to be disconnected. I want to make sure that it will bring me some tangible benefit. Which is why I was asking if anyone knew how much of a difference it would make.

 

[NRGarrott]

Yes a block off plate with insulation behind it will provide a very tangible benefit. If it is really a pain I would consider doing it when you clean the chimney. I made a template for mine out of cardboard, and then cut two pieces of sheet metal to fit. Each piece of sheet metal had a half moon shape, to fit the liner. I did not seal it with silicone, because it doesn't fit that great. I had a blower door test yesterday, and the technician was very surprised how little air came from the gap around my insert, that makes me think my method is good enough.