Hi,
Our new (old) house has hot water heat. I am very excited to use this type of heat. I hear it is more effecent overall (vs. forced air). I have never ran this type of heat before. The house has old style cast iron stand up radiators and a new boiler setup (like 3 years old maybe). It all is in very good shape. What is the best temp to run? And is it smart to turn down the heat when we go to bed or leave for work. Only the dog is home during the day. With gas prices going up I just want to be as frugal as possible. We wear sweatshirts anyway. Thanks alot for your advice.....

 

We love our HW radiators too. I'm certainly no expert but it can take a couple hours to reheat the house after a T-stat setback. You may want to plan accordingly.

We don't do that as I'm often up at night & home during the day. We keep our upstairs zone set ~62*F as heat comes upstairs. Good for cuddling but a bit cool for morning showers. In really cold weather we may boost it a few degrees.

 

Milemaker13, the ability of setback t-stats to significantly save money depends on many things.

- best with longer setback periods, where boiler even fires once or more at the setback temperature

- best with simple bang bang controls since an outdoor reset means longer recovery times and the reduced water temps will reduce the recovery rate so it takes much longer

- best with leaky houses that lose temperature really quickly

- not so good with condensing boilers because you'll need higher water temps to recover and lose some condensing

- not so good with houses the recovery unevenly

- not so good for comfort if there are objects of different masses in the house, big high mass objects will never feel room temp... because of this one might actually use a higher occupancy temperature than you would if it was a steady indoor temperature

Setting back reduces comfort and hurts condensing efficiency but once the temperature plateaus at the setback level, your heatloss levels are lower.

With a modcon, I'd only do a degree or 2. With a conventional bang bang boiler maybe 5, but your experience may be very different.

My advice would be that when it gets colder, first try a fixed temp for 3 days, maybe one degree cooler than you normally set the house if you are already setting the t-stat back. Then over the next week maybe every 2 days, reduce the temp by just a degree or even half a degree. It's amazing how much more comfortable a house can be without setback.

Once you've done that and established the magic minimum indoor temperature that is fully comfortable, then try very small setbacks during overnight and daytime unoccupied periods. Try and do the setback without having to raise that magic minimum indoor number. With a leakier home, you may need to increase the indoor temperature some just to be as comfortable, but to offset that you should be able to do deeper offsets.

Are you talking boiler temp? If so, it really depends on your boiler and controls. Any more information about the boiler, boilers and piping/distribution/radiators?

 

Wow, Thanks-
I will definatly have some more questions tomarrow. I don't have internet at home anymore ($70+ a month was getting us ). I want to go over what exactly I have... whats a condesing boiler? Vs. a standard boiler? I will have more details tomarrow, but the house is single story w/ basement, built 1919, new windows, probably no insulation except the loose fill in the attic floor, gas fired boiler. Thanks again for now!! Beer 4U2

 

and then insulate some more ...

The single biggest bang for the buck is going to be to insulate.

Go all around the house and caulk, anywhere you see a crack that air can infiltrate. Then, look some more.

 

One of the guys I work for had asbestos insulated boiler supply and return pipes. Those big fat diameter ones they used to have. He had another worker encapsulate the asbestos with those black foam tubes and taped all joints. Now the basement obviously feels colder.

But I wonder if that is cost beneficial, or if it is better to say insulate the basement walls and leave the pipes exposed in the basement, to help heat up the floor. Any thoughts?

I think the poster wants to know if the boiler should run say140 or 180. What, in a boiler or piping layout, would require a person to choose one aquastat setting over the other? In some old houses I deal with, that have boilers, I have seen it where the water temp never even reaches that LOW figure, because the call for heat ends before it ever reaches the cut off point. I guess likely because the temperature swing is set very low.

 

Didn't get much time time to look at the system thoughly, but it isn't very complex anyway. I have a newer boiler, newer expansion (bladder type) tank and new circ. pump. From what I know there is no zone controls or indivudal radiator controls. Where would my aquastat be in a system like this? I have a thermostat located about 4' up the living room wall, across the room from a radiator. The rads are in good orignal shape, even the bleeder valves are mostly orignal. They still work with the little key the widow was given by the PO back in 1956. My pipes in the basement are uncovered, and basically run a header/return and branches for the rads. Its just the one floor above the basement, so no upstairs zones or anything like that. I would think leaving them uncovered would heat up the basement well, but if insulting them would help overall I think the basement would still stay warm enough.... Its a pretty livable basement, not very dark or scary

 

Maybe, maybe not ... the title of the post was something like:

"What's the most efficient way to run my boiler" ...

And my answer, after reading that it's an older home, and probably without insulation, was to INSULATE.

I wasn't talking about insulating the pipes, I meant the HOME.

Because the most efficient way to run a boiler is to NOT run the boiler! The better insulated the home is, the less the boiler will have to run to keep up with the heat loss. Simple as that.

The better insulated the building envelope is, the less heat is lost. Heat loss INSIDE that envelope isn't really heat loss after all, because it contributes to heating the home as you said. If that old system was a steamer, then insulating the pipes is a necessity of design for steam systems. In that case, the insulation was done to encapsulate the asbestos though.

I doubt if it's got anything to do with the 'temperature swing' setting (whatever that is?). It's more likely that the installed radiation in the home is enough to satisfy the heat call with lower temperature water. If the heat call ends, it ends because the thermostat is satisfied. And, if the thermostat is satisfying, it may be because those old homes had been INSULATED, and now the amount of radiation in the home is enough to cause that satisfaction with lower temperature water.

On the boiler somewhere. Probably a gray box that says Honeywell on it. But, don't go turning down that aquastat without understanding what might happen if you do. Chances are very good that the installers didn't consider BOILER PROTECTION when they piped it up to that large water volume system. You may already have a situation where the flue gases are condensing due to return water being too cool. That condensate is acidic and will slowly (maybe not so slowly) eat your system. By turning the aquastat down, you will speed up that process.

The water temperature in the boiler must be hot enough to achieve two things:

1. Protect the boiler from corrosive condensation.

2. Adequately heat the home.

A condensing boiler is one that is specifically DESIGNED to be run at temperatures that will condense the flue gases, and extract that extra few percent out of the latent heat in the exhaust.

 

I read it Trooper. Thanks.

Since you mentioned about a low temperature can cause tit to condense, and this can be corrosive to a boiler not designed to condense, what signs might be visible of this, and what part of the boiler is first to get eaten away?

And the swing of temperature referal in my previous post: heat anticipatror setting on stat set to smaller number.

 

I guess the most visible sign might be whitish 'runs' coming from the seams in the flue pipe. These would start as liquid of course, and run out on the surface and evaporate. Someone posted some pics of this a week or two ago, but I forget which thread it was in.

For condensation inside the boiler, you would pretty much have to open it up to see... slight condensation issues might resemble whitish/yellowy 'ash' deposits. Worse cases you might find something like this:



These 'rocks' are about an inch or two in size, and formed in the flue passages inside the boiler when the dumba55 owner decided it would be a good idea to remove the jackets and insulation on the boiler to keep his pooch warm in the winter. At that time, he didn't know anything about flue gas condensation, and learnt the hard way! But the pooch did stay warm, rest his soul...

What would go first ? I guess it depends on where the condensation is ocurring. It wouldn't take long to rot out 26 ga flue pipe. In a masonry chimney, the mortar would go, the flue tiles would 'spall' and flake, in a boiler... hard to say ... probably at the seams between the sections where the stuff would collect ...

OK on the anticipator settings... they could cause a boiler to short cycle, or on the other extreme overshoot the setpoint, so yeah, they do need to be set correctly. I think most of the newer t'stats 'learn' the correct setting though... many don't even have an anticipator setting.

 

I have almost the same questions.

I currently have a 1909 2 story home + attic, with old windows and minimal insulation. I have a 1999 Burnham 198KBTU boiler. No zones except the manual valves on the radiators.

My focus is on the insulation and air leaks that is a granted. However, I would like to know if adding a boiler reset control would bring the return on investment? I know they don't help much when it is really cold out but during the fall and spring I think it would be helpful.

Also, due to the high cost of gas and our poor insulation we keep the house at 62F at all times (at 70Finside and 30F or below outside our bill goes to over $400/month). Would a programmable thermostat of any kind help or would it essentially hurt the system constantly fluctuating? If we leave for an extend period of time (the whole weekend) the thermostat goes to 55F.

Any help would be appreciated.

 

Sure a reset control would pay for itself ... do keep in mind though that with a conventional boiler and piping system you will be limited to only doing a 'partial' boiler reset. That means that your control will have a lower limit setting that won't allow the boiler to run cool enough to cause the condensation problems we are talking about. But even a partial reset is cost effective.

I would concentrate on the insulation/infiltration issues first, get that under control and then look at the boiler system for areas it could be improved.

Programmable setback thermostats won't hurt the boiler. They may not save much though if the setback period is less than say 8 hours or so... short setback periods won't really save much because the energy used recovering from the setback eats up the savings.

 

I would agree with Trooper; INSULATE.

I live in Toronto, built in 1925 Craftsman style home. It is wood framed brick, plaster walls, all original chipped glass doors and 8 inch high original oak baseboards and hardwood floors and until a couple of months ago, the original wood windows, but I digress

Anyway, we had a local company come in and evaluate the house with a blower door test for air leakage.

It was DRAFTY to say the least.

So, last November they came in and insulated the attic to R70, drilled the walls and packed in insulation in the wall cavities.

That operation took a week and was 7000.00

Even with oil prices last year of around 1.12 per litre for oil, vs the previous heating season of .80 and a colder winter, our heat bill was 700.00 lower than the year before.

It was admittedly a lot of money, but it is a long term investment, and the house is way more comfortable than it was before, and as well it was much cooler this summer so I am a convert.

just adding weather stripping and caulking around window casings and such will make a difference.

We'll see how much difference all the new windows which were added this summer make this year.

And for the best way to run a boiler, it is my understanding they are more efficient if they do not have big temp differences between cycles.

Terry

 

Second what Trooper said about the reset control.

And here's another vote for insulation and air sealing. It's the best thing to reduce fuel use, and has the shortest payback.

Think of insulation as fuel you buy only once.

Check out the DIY insulation and air sealing guide at www.energystar.gov for starters.

Knocking even 5000-10,000 BTU/hr off your heat loss by insulating and air sealing will save $hundreds per year.

 

Terry, heating with oil in Toronto is crazy. NG has gained more in price than oil, but it is still about half the cost per BTU. With natural gas you can lock in about 2/3rds of the price (the transportation is about 1/3rd) if you want to do that sort of thing. The weird thing I always found with oil companies was that they would have prices cycle up and down a bit, just like gas stations but less often and smaller swings... thing was, they always seemed to deliver at peek on their systems that they say are based of heating degree days. Mmmm yup.

Best side benefit of gas. Not having to take the propane tank for it's random filling, and then waiting for the tank to run out under wonderful but overpriced t-bones! Even switching tanks mid-flip wasn't fun or appreciated, and the tanks will rust through way too easy which makes owning 2 cost ($36/5yrs=$7.20/yr for tank replacement). Propane costs way more per BTU than NG, but a NG BBQ might cost $100 and will take require some extra piping and ideally 2 valves, one outdoors and one indoors for while you're away in case your neighbor's tank runs out.

You should look at a modcon for comfort and efficiency. You probably use an electric water heater, but an indirect fired water heater piped up to the modcon would be totally ideal. Between that and the insulation update you've done, your footprint will be way down. Next big thing would be solar DHW preheating...

 

The boiler in the house was oil fired and by boiler standards fairly new when we bought it.
When the current system bites the dust, then we'll switch to gas.

My wife wants a gas fireplace insert and the BBQ propane tank run out is a pain as it happens all too often as you describe, so another vote for gas.

Switching to gas will also allow us to get rid of the chimney, that right now runs through the kitchen and is a point of contention with my better half.

Please forgive me but what is a "modcon"?

 

A modcon is a modulating condensing boiler. These boilers allow excellent efficiency (especially in the milder weather) compared with conventional boilers as well as excellent comfort.