Oil to Gas Conversion

jefflaz

I've searched the forums for a similar issue, but haven't been able to find something exact.

A bit of background: we live in New York in an older home that was built in the 1890s. It's 4 stories if you include the attic. It currently has steam heat delivered through radiators. No central A/C. The boiler is powered with oil. The radiators heat the house quite well. Given the age of the home, there isn't much in the way of insulation in the walls. However the stucco exterior does provide some.

The boiler and oil tank are on their last legs. We need to replace them by next season. We have three options:

(1) Stay on oil. Replace boiler and oil tank
(2) Switch to natural gas. Replace boiler, remove tank
(3) Scrap the steam heat. Install a dual AC and heating system

We want to stay away from option 1. It tends to hurt resale. We had been leaning towards option 2 until seeing the price tag. Natural gas rates aren't cheap in our area, so we are essentially paying for a new boiler that runs on a cleaner fossil fuel.

Option 3 is what I am seeking some advice on. We eventually want central AC (or perhaps ductless units). I understand that dual AC/heating systems are inherently inefficient. Does anyone have experience with Unico's system in this regard? Like I mentioned, I doubt the difference in monthly cost (electricity v natural gas) will be material given NY rates. Basically, is it better/more economical to scrap the new boiler and go with a dual system? Or replace the boiler with a nat gas fired one and do the AC separately?

Jamie Hall

It's partly economy (by the way, please edit your post to remove the dollar figures -- we don't discuss prices here) and partly comfort. The most comfortable solution will probably be to install a new gas fired boiler. It will also not be much more expensive to run, and will be much the least expensive to install and will give the best comfort in colder weather.

New, advanced heat pump systems are pretty efficient, even at very low outside temperatures (there are some that claim good efficiency even at 15 below). They are not cheap. Further, if the house has not already been heavily remodeled, installing such a system -- even a small duct high velocity one like a Unico -- and removing the radiators will damage the historic character of the house -- which will also hurt the resale value, perhaps by quite a lot.

jefflaz

Thanks Jamie. I removed the references to cost.

We ultimately want some sort of cooling system. The window units are massively inefficient. It seems as though many historic homes go with Unico/Spacepak due to the discrete nature of the ducts and the lack of major renovation work to install. Is the latter inaccurate?

STEVEusaPA

Modern oil boilers are much more efficient than what you have in there now. So a more efficient boiler (sized by your EDR), combined with your high nat gas prices (they probably aren't ever going down), and the many recent and growing problems with natural gas distribution, would tell me to stay with oil.
Option number 3 isn't really an option. I'd hate to see you rip out the steam. But you could add an air handler in the attic and one in the basement (depending on logistics) and have AC.
I wouldn't even think about mini splits in general and specifically with an old historic home.
Oil is only problematic for resale if you let it be. New boiler, new tank (or even a double-walled Roth-like tank) and you should be fine. It's not problematic in areas that only have oil.

Brewbeer

I'd stick with steam and install A/C as needed, and if you are upstate, I'd stick with window units. Compared to the steam heat, the heat pumps will leave you feeling cold.

Jamie Hall

jefflaz said:

Thanks Jamie. I removed the references to cost.

We ultimately want some sort of cooling system. The window units are massively inefficient. It seems as though many historic homes go with Unico/Spacepak due to the discrete nature of the ducts and the lack of major renovation work to install. Is the latter inaccurate?

First, on oil vs. gas -- I personally would find gas a real turnoff, particularly with the increasing problems with supply. Nothing wrong with oil. But opinions do vary, and sales pressure from the gas companies is pretty fierce.

Many historic homes do go with Unico/Spacepak type systems. So do museums. If it is necessary to have some sort of forced air air handling system, they really are the only way you can do it without basically demolishing the historic accuracy of the structure. How much demolition and cost is involved in the installation are very much a factor of the nature and construction of the building; sometimes it is relatively straightforward. Sometimes -- stone buildings, post and beam, high quality plaster finishes -- the cost can be truly astronomical and is justifiable really only if you need tight control of both temperature and humidity. If you really need A/C --which is a luxury item -- @STEVEusaPA 's suggestion is probably the best approach. Part of the reason for this is that the amount of heat -- and thus air movement -- required for heating at all comfortably (that is, draught free) is much greater than the air movement required for cooling, and thus both the units for heating and the ducting are correspondingly bigger.

If you have a functioning steam heating system -- except for the boiler -- much your best bet is going to be to keep it and bring it up to modern standards, and, if you do need air quality control or cooling, provide that with basement or attic air handlers.

SlamDunk

You should keep the steam, It is much better at keeping an old house warm.
When sized right to match your load and installed properly you'll find it economical to operate.

Gas or oil is your choice. It is not easy or fast to switch to gas in NYC. But oil prices can be volatile.

I would add the cooling as mentioned above and keep steam.

nicholas bonham-carter

Don’t forget to get a real steam expert in to do this replacement.
He will measure all the radiators, in order to choose the right size, and he will follow the piping instructions from the manufacturer at a minimum, otherwise you will be back here, seeking advice on curing various problems.
The new system will be even, silent, and possibly more economical than before.—NBC

jefflaz

Thanks everyone. We are going to stick with steam heat. Question on boilers:

We were sized for a Weil EG-55 with 167k BTU of capacity. A few people I have spoken with have recommended Buderus instead. Are there material differences between those two brands?

Jamie Hall

Before you decide on the size of the boiler, be sure to add up the EDR of all the radiation in the house. The new boiler should have an EDR rating equal to, or even perhaps slightly less than, that sum. Anything bigger is wasted.

Have you done that?

There are significant differences between the Weil McLains and the Buderus boilers, but both of them are very good boilers. More important is what boiler is your installer familiar and happy with.

Steamhead

Buderus doesn't make steam boilers.

Jamie Hall

Steamhead said:

Buderus doesn't make steam boilers.

My bad. I forgot... I was thinking Burnham. Getting old.