Upgrade Advice on Strange System in 1906 House

JDB75

we have been renting a whole house from our LL since 2016; she's in her late 70s and is considering selling to us in the next 2-3 years. The house needs upgrades across the board but one major is the heating system. It's a 1906 brick/stucco house of 5500 square feet. The gas company inspectors have told us it has a "mother of all gas mains" coming in and the system is strange - on the ground floor, four rooms and and main hall have huge forced air registers. air is blown over radiators in the giant ducts in the basement. The kitchen, pantry and half bath have hot water radiators or those horrible electric baseboard looking ones that barely heat. All rooms on the 2nd and 3rd floors have giant hot water radiators in fact, two of the biggest rooms each have a 12 foot stretch of them. Our gas bill (heat/hot water/dryer/cooking) jumps from $200-250 in the summer to $1250-$1400/mo in winter months. Some of the hot water pipes for the system coming out of the boiler are cast iron 6" diameter.

So, what might be some options for upgrading/replacement? What is our system even called? It's split but I never saw forced air with the air being heated by radiators in the ducts (which are HUGE).

Steamhead

Those are "indirect radiators". Originally the air circulated through them by gravity. If they now have fans, they must have been added later.

Where are you located?

Brewbeer

Full house, room by room heat loss assessment is the first step. An $8,000 year gas bill suggests some insulation and envelope tightening upgrades should also be on the table. A few years ago I had to replace the heat in my house, and opted for a low temp baseboard system fired by a modcon with indirect for hot water.

mattmia2

Make sure those indirect radiators use air from inside the house, it wasn't uncommon for those to bring in air from the outside.

Ironman

Upgrading to a mod/con high efficiency boiler can typically cut 30-40% of your heating cost. As mattmia2 said, having the indirect radiators reworked so that they're not pulling in outdoor air will also help greatly. However, be careful about how the re-ducting is done so that air is still drawn over the radiators.

Somewhere in the resource section of this site there's info about indirect radiators and even an interesting story by Dan Holohan.

Jamie Hall

Agree with all of the above, plus some comments. First, although it has been said explicitly, that was gravity hot water originally. Those are a little tricky to get properly balanced with modern boilers, but by no means impossible -- and except for modern additional radiation or the electric baseboards -- can be made to work marvelously well. You do need to find someone who knows what he or she is doing, though. And yes, I would suggest a mod/con for the heat source.

Also as has been said, tightening up the house will save you money. However, before you start doing that, determine what you really do want to do. Specifically, do you want to restore the house or to make it into a "modern" something or other. If it hasn't been too badly hacked, there is much more value in a restoration than in trendy upgrades.

One of the first things to tackle is windows. Unless these have already been replaced, you will do far better to get the original windows repaired to be as tight as they were when new -- which isn't hard, just painstaking -- and get either inside or outside storm windows. Much less costly than modern replacements -- and will last a lot longer and do as good a job.

Other air leaks -- see what you can find and stop them up. It's very unlikely that you will get the house so tight that air quality suffers, so have at it.

Insulation. It may be -- usually is -- easy to insulate the attic and roof, and that can make a tremendous difference. It may or may not be easy to insulated the walls. In fact it may be almost impossible to do without major damage to them -- in which case, I'd leave them alone and not even try.

There is a lot of help out there for restoring older structures, such as local historical societies or state historic preservation offices -- or the National Trust for Historic Preservation -- all of which can help with either "how to" direction or finding craftspeople who actually care about your house.

Erin Holohan Haskell

Ironman said:

Somewhere in the resource section of this site there's info about indirect radiators and even an interesting story by Dan Holohan.

Here's a video on indirect heating systems: https://heatinghelp.com/systems-help-center/indirect-heating-systems/

And an interesting story: https://heatinghelp.com/blog/solving-a-problem-with-indirect-heating/

JUGHNE

What water temp is needed to heat the house now?
For a rough experiment:

Could you lower the temp to see at what point the house becomes uncomfortable?

You would have to consider the outside temp as you analyze this.

You need to return the boiler temp to a place where you have 130-140 degree return water temp after any observation.

ModCon boilers achieve their max efficiency with low temp return water.
The indirect coils with fans may require higher temp water than the standard radiators do to maintain comfort.

JDB75

Hi - Wow - thanks for all the feedback thus far. The house envelope definitely needs work - original single pane windows in some rooms, single panes with storm windows in others but I can feel the cold air coming in still. And the 1950s addition kitchen/pantry/bathroom has some mid-century single pane windows.

Boiler has 2-3 pressure tanks? one of which needed replacing. I recall the boiler temp being at 160. The thermostat is right at the top of the 1-2 floor staircase and needs to be kept at 68-70 to keep the house comfortable when the outside temp is 28-35, for example. This house has at least 75 windows total.

Brooklyn - Ditmas Park location. Most recent 31-day natural gas bill was $1279.

Not aware of any outside air required for forced air part - there are return registers. Ducts/registers feeding the hot air push it out very weakly. Air is hot but these 3'x1' and 18'x18' registers push it out with the force like someone is breathing on you. Return registers are also full of junk/hair/dirt!!!

mattmia2

Certainly getting weather stripping and storm windows on the windows will help and air sealing anywhere else you can, but that is a huge house, that bill doesn't seem unreasonable not knowing your cost of natural gas. If/when you replace the boiler or maybe even before you can add separate zones to replace the electric baseboard(or it might be fin tube hydronic baseboard, i can't tell from your post, but that heats very differently from cast iron and needs to be on its own zone). You could replace it with fin tube baseboard or you could use panel radiators. The radiators will be more comfortable.

The system should only need one expansion tank sized for the volume of the system, unless there are multiple systems separated by heat exchangers or something(or an expansion tank for the domestic hot water because it can't expand back to the main for one reason or another).

EBEBRATT-Ed

Check "find a contractor" on this site Maybe @JohnNY

I would strongly suggest insulation/windows/doors before replacing the boiler Any boiler you install now would be much too big after the improvements

PC7060

@JDB75 75 "Our gas bill (heat/hot water/dryer/cooking) jumps from $200-250 in the summer"

wow, that seems high for summer gas bill, how many therms was that? How many therms did you use in last month or so?

Does the 5500sft include basements?

The video Erin posted on Indirect Heating is very interesting and could explain a lot of the high cost of heating.

Jamie Hall

On the windows -- a favourite topic o mine -- it is almost always better to get a craftsman to repair pre World War II double hung single pane windows and add storm windows -- either interior or exterior -- rather than to rip them out and install new windows. The new window salesman have a pretty convincing spiel, but the fact of the matter is that unless you opt for the very very top of the line, most expensive models they simply don't last -- and don't do any better at keeping the outside out than the originals.

The mid-century windows are another question, though. They probably will be better repaired and equipped with storms -- particularly on a house like that, as they may have been done well -- but they need to be evaluated.

PC7060

Jamie Hall said:

On the windows -- a favourite topic o mine -- it is almost always better to get a craftsman to repair pre World War II double hung single pane windows and add storm windows -- either interior or exterior -- rather than to rip them out and install new windows. The new window salesman have a pretty convincing spiel, but the fact of the matter is that unless you opt for the very very top of the line, most expensive models they simply don't last -- and don't do any better at keeping the outside out than the originals.

The mid-century windows are another question, though. They probably will be better repaired and equipped with storms -- particularly on a house like that, as they may have been done well -- but they need to be evaluated.

Echo what Jamie said, good high quality storm are very effective AND can look good. I use Vel-A-Lume (approved by National Park Service) storms on our house in a listed neighborhood. I like the look and the design allows the window operate well even with out of square frames which is typically a killer for windows.

TAG

5-6k is never going to be cheap to heat. I redid both a brick 4 story 5000sf in Philadelphia and a 6k victorian in Chestnut Hill. Something is up with the use in the summer .. what's making the domestic hot water?

Redid both of those places with two Buderus Cast Boilers in each and indirect water heaters. They used outdoor reset with the old radiators. The Victorian had more structural changes -- so it got more radiant and panel radiators in odd places. The city property just the baths and kitchens got some radiant. Be careful with anybody wanting to rip out and replace parts of the old systems .. I was lucky and found an old timer who actually had worked on my chestnut hill house back in the 60/70's when he was a kid working with other old timers. Still a generation away from when it was built in the late 1890's. This was back almost 20 years ago ... Lots of dumb things were done to mine that had to be returned to the way it was.

I second the windows .... they are a lot of work (redoing) .... but nothing destroys a house faster than cheap replacement windows. It almost always best to fix what is there ... even if they need new sash.