Do you know if the home was built with green lumber or kiln dried lumber? Allowing the home to dry is always helpful but not necessary if your builder used kiln dried material to frame your home. The most critical time for temporary or permanent heat is when you are ready to install drywall and begin taping during cold weather. How long has the shell of the home been closed in from the weather?

The house has been closed for about 4 weeks maybe 5. I'll have to find out what kind of lumber has been used. My cousin who is a GC said its drier in the winter than the summer and rather than heat I should rent a large dehumidifier if he's worried about the moisture. My contractor just seems to think the moist cellulose insulation being installed over the "moist" wood is going to be an issue. My issue is the dollars flying out the eves.

If you turned on the HVAC in that condition.....it's gonna cost BIG bucks. It'll be on 24/7...!!!!!!!!!!!!!

I forgot to add....WHY is the lumber wet to begin with? Did the GC forget to raise the lumber off of the ground and cover it if it rained or snowed before being used?

Use dry dense pack cellulose and avoid all the nonsense associated with wet spray cellulose.

There is a limit to how much $$ your furnace would use in a few days. Even if it did run 24/7, and it might not given the sun and setting it at 50 degrees, you might be looking at $30 a day. That is crazy money if you were living there but it isn't exactly crazy money for a few days.

That $30 is pulled out of thin air but it should be really easy to calculate what your furnace could do.

I just did the math for my house (in a more temp climate) and at full bore it uses a therm every 2 hours (50,000 btu) and a therm around me costs $.90. (so about $10 a day) So if you have about 150,000 btu (which seems to me would be crazy even in Chicago with 5000 sq feet), you would be at about $30 a day.

I really really love that you are concerned about wasting fossil fuels and the concept of running your heat without insulation disgusts you. But, you are not exactly driving a Hummer here.... No whether his argument about moisture holds water, I don't know. Generally, the RH is so low in the winter than anything would dry out very fast. Raising the temp a few degrees wouldn't hurt. Keeping the windows open and lots of wind wouldn't hurt either.

I agree, what is a few dollars for a few days balanced against future problems.

There can be many reasons to dry a home out, from concrete floors to rain or snow before the roof went on.

Ours was for drywall concerns, not insulation, but we had to fire up before we really wanted to also. (geo not quite ready to go yet so using electric strip heat) The first day to warm the house up, it was like $40 then in the $30's and now it has evened out to about $20 a day. About the same as running loud smelly kerosene heaters.

But I look at it like this, it is either this, or wait till Spring when it warms up.

The time to dry out the house is after wet spray cellulose is installed. I suspect the reason for heating it now is to prevent the cellulose from freezing during installation.

Obviously, installation of wet spray cellulose in cold temperatures is not a very good idea. Dense pack is a no brainer in this situation.

If you install wet cellulose in cold weather, indoor temperature and humidity must be carefully controlled to avoid freezing of the insulation within the wall assembly. You will need to provide supplemental heat until the moisture levels throughout the insulation reach 25% or less. Unfortunately, it is also critical to ventilate moisture to the outside so even after the insulation is installed you will be heating the street at great expense.

You should ask your contractor why he wants to use this type of insulation in this climate.

From the Cellulose Insulation Manufacturers Association Technical Bulletin #3:

10.0 COLD WEATHER SPRAYING

10.1 SCWCI [Sprayed Cellulostic Wall Cavity Insulation] can be applied successfully in freezing conditions. Always consult the manufacturer for recommendations on spraying in severe climates and conditions. Some guidelines when spraying in winter conditions follow.

10.2 Heating the building while spraying is necessary if the temperatures are below freezing. In below freezing temperatures, the entire spray system can freeze up. The most vulnerable is the pressure hose and the nozzle. The pump and the inlet pump hose can also freeze. When the building is heated, these items may be inside.

10.2.1 When spraying inside a heated building the comfort level is much better. With higher humidity, the cold can be
more severe for workers as well. It is not necessary to heat the building after the spraying is completed. It is much more important to open all the windows and let the air move the moisture out.

10.2.2 The SCWCI will take longer to dry in colder climates. If ambient temperatures are expected to drop below 40° F before drying is completed it may be necessary to use supplemental heat until moisture content measures 25% or less.

10.2.3 If heat is used during the drying process, it is imperative to have ventilation to the outside. Selecting the type of heat to use is also very important. Dry heat, such as electric, works the best. It will speed up the drying process. Propane or gas heat can add high percentages of moisture and should be avoided. Remember, whenever heat is used you must make provisions to ventilate the moisture to the outside of the structure.

First off, thanks you all so much for your informative responses. To have kind unbiased knowlegable people helping out is a GODSEND. I called the insulation company and they said they would come out and spray the attic area first then we can heat the house for a number of days and they would come out with a moisture meter after that to check the level of moisture before application, if they have to wait a few more days to do that, they would.

They install the dry dense pack as well and he seemed to feel they both do the same type of job as far as insulation value but that sometimes the dry dense pack will "pillow" and the drywallers have or complain that the job is more difficult. Opinions??