Dockside Chat - Thinking of changing my heating system

My shore homes heater is a forced air system, it sits on a crawl space and is a raised ranch of about 1,200 sq.ft.

The heating system is original form the mid 70's and in winter is constantly on. The blower comes on, then the heating unit kicks in, warms the house, shuts down and the blower blows for another minute or two and shuts down. No sooner does it (blower) shut down then it starts back up again and continues the process.

The unit itself is located right behind the main bedroom wall and at night is extremely annoying, loud with vibration.

I don't use the house much in winter but when I do I want to sleep at night, it seems worse these past couple of years.

Figuring the unit is on its last legs (age wise) I want to change it out but am unsure as to what type of system to get.

I'd like to keep costs down both with the new system/install and cost of use over time. Is a forced hot air system the way to go (the duct work runs under the house) or should I get a hot water system like baseboard or maybe some other type?

Generally, when the heating system acts that way, either the thermostat is faulty or else the t'stat heat anticipator is set incorrectly. If you replace the furnace but keep the current thermostat, the new system will probably act the same. What kind of thermostat do you have?

Replacing that old furnace with another forced-air unit is probably the most cost-effective way to put in a new heating plant.

A mid 70's unit is probably 82% efficent, 86% at best. Today's system can get you all the way up to 98% (forced air natural gas).

If your system is oversized it can short cycle.......aren't your winters getting colder these past couple of years? What sort of R value do you have in the attic, maybe that should be increased? For heating and cooling I would think you should have upwards of R 50-60 up there....insulation is cheap compared to heating/ cooling costs. What R value do you have in the floor, maybe that should be addressed?

Stay with force air gas, it's your cheapest route.

Thanks, I don't know the "R" value off hand but there is 6" of the pink stuff in both the attic and under the floor. I did the floor myself about 5 yrs ago, the attic was done when I bought the house and yes I should add more there and will.

The thermostat is an older dial type and I don't know what brand if it matters but can find out. I'll have to look up the BTU on the unit also. Am thinking of insulating the ducts that go under the house in th crawl space too but not sure what kind of insulation to wrap them in.

If you pull the cover off that old thermostat, you should see a small scale calibrated from, say, 0 to 2 with .1 increments. There will be a small pointer on the scale, typically the correct position for the pointer is the current required by the furnace gas valve, which can be 0.2 to 0.6, typically, and is printed on the gas valve. That scale and pointer is the heat anticipator adjustment. With the symptoms you describe, I'd move the pointer one notch towards the word "longer" or towards a lower number. That should cause the furnace to run a little longer in a cycle, resulting in a slightly higher final room temperature and a longer delay before the system turns back on again. Make small adjustments, see what effect it has.

This all depend son the local fuel prices. Right now many CT customers where gas is not available are paying more than 4. for propane which is MORE expensive than electric heat at that rate.

Old oil units at even 80% efficiency are way cheaper. Check they amt. of BTUs you get per buck. I can help with the calculations if you want. Other than wood - Natural gas does seem about the best buy now if you can get it.

Thanks, won't be able to test this out until we get a cooler spell but will check it out when I can and give a report on what happens. It is a NG set up.

You have multiple questions that have little to do with each other.

The short cycling of the blower/thermostat is your first problem and has nothing to do with insulation or furnace efficiency. As yarcraft pointed out, it's probably the heat anticipator. You can test the amp draw of the control by disconnecting the thermostat wire from R or RH and W. Then you need a clamp amp tester and a piece of wire. Then.............

I could walk you through the test, but the simple and best answer is to get a new digital thermostat and follow the directions. When reading the directions, pay attention to proper placement of the thermostat.

To answer other questions, what is the source of heat (what is the fuel)?

The condition of the ductwork needs to be considered, especially the duct insulation.

A heat loss calculation is very important when deciding size, wont matter as to what type of system. You "don't use the house much during the winter" would indicate it sits unoccupied and thus I would suggest warm air.

"It is a NG set up." I just saw this, so that answer's the question of what fuel. NG is good in this case.

Depending on it's condition, I'm not sure you need a new furnace. For your use, efficiency isn't a big factor.

Older natural gas furnaces have a pretty long life expectancy. A new furnace will be best in the long run, but probably not a solution to your immediate problem.

Many insulation companies will wrap the ductwork and will be a lot less expensive than a HVAC company.

"It is a NG set up." I just saw this, so that answer's the question of what fuel. NG is good in this case.

Depending on it's condition, I'm not sure you need a new furnace. For your use, efficiency isn't a big factor.

Older natural gas furnaces have a pretty long life expectancy. A new furnace will be best in the long run, but probably not a solution to your immediate problem.

Many insulation companies will wrap the ductwork and will be a lot less expensive than a HVAC company.

I don't mind crawling under the house to wrap the ducts, just not sure what to use. I may just change out the thermostat and see if that does the trick, but will follow up on the above recommendations first.

You said your attic insulation is 6" of fiberglass and you plan to add to that. Good, as there is no part of the US where that's adequate attic insulation. 6" in the floor, fine in most places.
http://www.energystar.gov/index.cfm?c=home_sealing.hm_improvement_insulation _table

I don't mind crawling under the house to wrap the ducts, just not sure what to use. I may just change out the thermostat and see if that does the trick, but will follow up on the above recommendations first.

For duct insulation, it depends on what you have. Sometimes, the duct installer used ductboard for the trunk and flex duct for the branches. Others used metal duct wrapped with insulation. Some used all kinds of stuff. Most likely, nothing you have is up to code, but you have to be practical. Pics would help with recommendations.

Air leakage in the ductwork and the house may even be a bigger problem. Also, a grossly oversize furnace will cause some of your problems as well as being inefficient.

Proper placement of the thermostat is very important.

As mentioned, old furnaces can last a long time.

Don't worry about trying to reset the heat anticipator, change it out to a new Honeywell digital. If you have only 4 wires you may have to run it on batteries which will last yrs.

The vibration is likely the blower assembly. (hire a pro:grin:)

Or, pull the panel off (at your own risk of electric shock) and look at the blower and see if it's vibrating. Maybe there's a broken mount, maybe there's a mouse in the squirrel cage. Maybe there are blades missing off the blower wheel, maybe there are weights missing off the blower wheel.

Depending on the age of the unit maybe it's not the blower but the inducer motor vibrating.

My best advice: ask your neighbors who they use for service and are happy with and get a pro in there.

My guess for a 2nd home blower vibration: varment, critter, plastic bag, that air filter that went missing, you wouldn't believe some of the things I've found.

Thanks guys for all the advice, will look into it all as soon as I can get in and the temps are right.

The duct work under the house is metal/maybe alum. and I don't think it is insulated at all, the tubes coming from the heater itself are about 4-5" in dia and non are wrapped with anything. If there is air leaking from the connections I haven't found any but in an old system anything is possible.

You can buy a role of duct wrap from any HVAC supply house or over the Internet. First thing you'll want to do is tape all joints with "metal" tape.

FYI, I'm highly allergic to fiberglass. I had a job that the usual guys couldn't be there for and I had to do the insulation by myself. I used a "bubble wrap" insulation made for ductwork. There is a special stapler for the fiberglass wrap (I think I still have it and you're welcome to borrow).

I'm sure both processes are on You Tube and I'll see if I can find something.

Use mastic membrane and staples for fiberglass duct wrap , tape won't stick to old insulation .
2" duct wrap to meet my area code 11/2" in others . anything over 24" needs stick pins under it or it will sag and collect water .
Nasty job and a cheap one to hire someone for .
Wash arms and face with cold water as cold as you can handle , making sure you wipe out your pours in the direction hair lays on your arm. Then hot water to open pours then cold again . Never use hot first or you will itch for days .
A trick for your arms is to coat them with petroleum jelly or use a white bunny suit from home depot .

Good information here. It also sounds like you have an older drafty house. Seal that sucker up and insulate the ceiling/crawl areas very well.

Here's a curve ball....pellet stove?....

Here's a curve ball....pellet stove?....

forsale ?

Thought about it for a quick second, not sure it will work for me or should I say wife? Thanks again for all the advice!

That's the reason this place is the best site I hit.