DV fireplace cold draft, options on table

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New Member
Oct 1, 2023
SE Connecticut
Hi All. First time/long time. I've exhausted searches on topics here for a good 3+ years on all options we've considered. Looking for confirmation on direction and info digested so far and whether we are going down a path that may not fulfill goals.

Issue: Existing home has DV propane insert that drafts cold air in the winter to the point we don't use it anymore and blocked up vents plus removed the leased propane tank. I've tested 41 degree temps coming in corners of insert when it was about 15-20 outside. It's the coldest room in the house outside of basement We finally decided 2 years ago to find a replacement/options.

Existing home specs: in SE CT, early 2000s colonial, 1700 sqft, 2-story w/ partially finished basement that has finished ceilings in all but boiler and water tank rooms. 2x4 build and well insulated including attic and 75% of basement. Primary heat is baseboard hydronic water via original oil boiler. Direct Vent is Lennox EDV-Elite Series propane insert in 12x14/open living room chase. LR is on north side of house w/ open room to nook and kitchen. Chase on NE side and chase sits on foundation into basement and extends to first floor ceiling. Domestic water on hybrid WT HP, which can be swapped to boiler when power is out. We have a non-inverter genny w/ a hookup in panel that comes out often, as well as kerosene heater in emergency. We've had periods of 4-8 days w/o power on at least 5 times in the last 10 years, on top of occasional 4 hr-1 days outages from storms. Having heat is always a priority. Side note: considering mini-splits to move to primary heat/cooling due to boiler starting to show signs of age and hydronic line deterioration (another project slated for this summer) and use boiler as backup/primary in coldest winter days. We do not have solar. Considering home review as part of 2023 IRA and using incentives where we can.

Goal: Initially, replace existing propane insert, insulate/closeup drafts in chase and use as a supplemental/occasional heater, as well as possible emergency heat when power is out for considerable time. Heater type: well, that's where it gets complicated...Wanted a WS, but house was "fighting me" in any location to put it, except LR chase, basement chase, or basement wall w/o some significant project increases. Now, new modern DV propane insert replacement in LR chase.

Options we've considered: ZC wood in chase, FS WS in chase to alcove, pellet insert in chase, pellet in basement, FS WS in basement chase, to finally replacement w/ modern propane DV insert in LR chase. I will keep models off discussion for now as I have a binder of brochures and quotes. We've had several contractors in to propose many of these options, Some would never be on the same page as to best option or why we had the issues with cold drafting, which was frustrating. Now, due to costs and asthetics we've crossed off WSs and pellets, as we thought that a DV propane insert replacement might be the solution until I started researching issues with drafts in DV gas inserts - it seems like they are common. Would a block of plate help (I don't think we have that as I can see light when I look thru the insert glass to the pipe. We're concerned that replacing a DV propane insert with a modern version of the same and even alum taping/insulating the chase may result in the same issue - cool air still drafting in come next winter. From what I've read this is the nature of the beast. Is it worth spending this money when we may be back in the same place next year, but maybe mildly less drafts? We tried looking at every corner of this house to get a WS in and settled on either the LR chase, basement chase, or basement FS wall w/o putting in major overhauls to existing home design, which we do not want to do and why they were pulled off the table. We didn't like the look of a pellet flame in an insert. I'm ready to close up the LR chase and call it good or just throw a WS or pellet in basement and deal w/ those issues.

To summarize, do we just have a poorly installed DV insert to which a new modern DV insert would solve this issue as they are better sealed and we could better insulate this chase to fix drafting issues? Trying to decide on staying the course on a propane or table that now as we may like the unit we select, but may have same issues again.
Not to get too picky, but your terminology is incorrect. You do not have an insert. You have a gas fireplace.
Secondly, it was most likely installed with minimal insulation and sealing of any air gaps in the chase. I installed DV units with insulated sheetrocked walls sealed with acoustic caulk. All seams & penetrations on the fireplace are sealed with aluminum tape. A Sheetrock deck is installed above the unit & on top of that is more insulation. Each of these steps will mitigate cold air penetration. Another factor is that your steel box will “reverse convect” air flow, since it is located in an unheated chase. When you’re burning the blower will draw cooler air across the floor into the valve cavity & move it up past the rear of the firebox & across a heat exchanger to warm it. When not in use the warmer air is drawn into the cold vent, & drops behind the firebox. This creates a cold draft at floor level.
If you can remove the unit from the wall & seal everything , your room should be better heated…
Thanks @DAKSY . I read many of your replies on propane stoves and some were similar threads about cold drafts in these fireplaces. Don’t ask me why I said insert vs FP as I knew that. I don’t think I saw how some people ended up after they either put a new gas FP in replacing their old one or had similar drafting issues. If I continue down an insulate and replacement path, I’ll be sure to come back to this thread with results.

Onto reinsulating, I’m looking at a spring/summer removal of the old FP and evaluate the current insulation state. Sadly, the brick facia has to come off to get the FP out, which is fine as we’d rather go with a stone face next time. It was always part of the plan to address possible insulation issues. It sound like from your reply above and previous threads, that when the unit is not used and cool, and it’s cold outside, negative pressure or reverse convect flow can occur and reverse air to come into the unit and out the from lower vents. Is that still common and an expected behavior in that it will be cooler near the FP when not in use and it’s cold outside? My concern is that after insulating and a new unit is purchased, we may have similar deep winter cold drafting issues and I threw money away. Or, will just insulating here solve most of the problem and I should not worry about the newer FP units cold drafting into the LR? Is aluminum taping of FP seams common to request or unnecessary in newer units? I appreciate your time.
As long as that firebox is exposed to the colder outside temperatures, reverse convection is probable. It is for this reason many manufacturers offer a Constant Pilot Mode. Even an approximately 800 BTU/HR flame can generate SOME heat, & that can mitigate the effects of that coldness. When you seal your chase, make sure you also seal that gap around the vent at the wall thimble, by using flat tape gasket. Your new install will not be completely resistant to cold because the cap is directly exposed to the outside conditions & can transfer some of that coldness thru the DV to the firebox.
Good luck with your project & keep us updated.