nycll said:joey791 said:chris13579 said:wale said:Had blown insulation added to our 120 year old once drafty Boston house.

This summer, a very damp summer, we found mold growing on the walls in several places. Papers were damp, envelopes were sealing themselves and everything was damp like it was in a steamy shower room. And now that the cold air is settling in, the house is outright freezing. We can open the windows to warm it up. I don't understand why it's colder in the house than it is outside.

It wasn't like that before. What happened? How can we cure the indoor climate?

I'd assume more ventilation such as keeping windows open, but isn't that contrary to the concept of insulating the house?

Since no one else has answered, I'll try, but I don't claim to be an expert.

For moisture control, make sure you have (and use) vent fans in bathroom and kitchen, to remove excess moisture at the source. Also make sure the fans blow air outside the house (not into an attic or crawl space).

If you have central air, it's now likely running less due to the additional insulation, so you may need/want to get air flow (fan speed) adjusted to increase dehumidifying effect.

If that's not enough, you may need a dehumidifier.

As far as indoor temperature, understand that your insulation slows down heat transfer into and out of your house. During periods with warm days and cool nights, it now takes much longer to feel effects of outdoor temperature on your indoor temperature. So on a warm morning after a cool night it may take many hours for indoor temperature to warm up - so opening the windows is a good idea to be more comfortable and avoid running your heating system.

Once you get used to it and make necessary adjustments, you should be happy with your insulation and lower heating/cooling bills.

In a nutshell if you had a 120 year old uninsulated house and depending how much insulation you installed your HVAC equipment is now way oversized. You are seeing an increase in humidity because the unit is now short cycling and not running long enough to pull the humidity out of the air. Now the heating side without looking at the unit it would be hard to tell.It could also be that the blown-in foam trapped moisture which is supposed to escape to the outside. That old house is supposed to stand for another 100 years, now it just started to rot.

Even I, really unknowledgeable about this stuff (or so I thought), would never have answered like that.

Foam is sprayed, cellulose is blown and cellulose does not create a vapor barrier.

I can install gas hot water heater that came with my house and is still sealed in the box, but don't know if I'm better of getting a more efficient one. It has an efficiency of 0.55 which is really at the low end.

On this chart, the cost of operating one rated at 0.65 over 13 years is $5220, and one rated at 0.60 is $5394. It's calculated at $1.40 therm for gas. I just paid $2.00 per therm on my last bill making the estimated costs significantly higher. I'd extrapolate an operating cost of $5568 from the chart for the .055 efficiency factor, and that would make the operating cost almost $7,000. Having an energy efficient one would cost $6525. Conclusion is that the old energy guzzlers a better one to use because I'd spend about the cost saved in fuel to buy a new one.

Am I really better off not buying a new more efficient unit? Does the cost of a new unit really wipe out any savings on fuel?

This seems to defy logic. I don't know if these figures are valid. Could someone more familiar with such estimations help out?

Well, even if gas goes up 30% the numbers would be $9100 vs $8482 total lifetime operating cost, a difference of $618. It just doesn't seem enough of a savings to invest in an energy efficient model which, again, seems to defy logic.

On reliability, I'd assume a similar lifespan but who knows now what the newest generation of heaters will do years down the road. Maybe they'll have a shorter lifespan... it seems the new hot water boiler heaters are being made with thinner walls to transfer heat faster and that they don't last the same 40 years as the old energy guzzling heavy casted one's did. Would something similar apply to a gas hot water heater? I have no idea.

dancingdesert said:Checkout a good analysis of tank-less hot water heater cost analysis by Joe at Home Energy WebJust looked at it. Kinda funny that in his detailed analysis of tankless as an investment, he assumed the tankless installation price would be "$500-$1300", but then I found he posted in his tankless blog update that the price he actually paid for his tankless was $2500 (for the unit cost + installation labor.)

So for an investment he predicted would payoff by $85 in present value, he made a present value cost overrun of $1200 to $2000. Doing the math, it seems that according to this own investment valuation, he would be seeing a predicted loss of -$1115 to -$1915.

However, one important factor that he overlooked, which might help his investment actually pan out: increasing cost of natural gas over time.

Actually, after reviewing my blog post and receipts, the final installation cost of $1400 included relocating the new unit to the basement from the attic (value ~$200), which would have been done regardless of what type of water heater I purchased. If this cost is removed from the calculation, then the NPV is more like +$200.

The key benefit of a tankless water heater is that it consumes less natural gas. So as natural gas prices increase, my monthly energy savings (relative to a conventional tank water heater) grow, which drives the net present value higher.

****News flash****

Obama to subsidize much more generous tax credits than were previously available for various residential home energy improvements, starting three weeks ago! (January 2009)

From energystar.gov...

Installation costs ARE COVERED for:
* HVAC (Heating, Ventilation and Air Conditioning) systems [<- includes high efficiency furnaces, boilers, A/C]
* Biomass Stoves
* Water Heaters [<- Solar and Tankless]
* Solar Panels
* Geothermal Heat Pumps
* Wind Energy Systems
* Fuel Cells

The tax credit for HVAC, biomass stoves, and tankless water heaters is 30% of the total cost (product + installation) up to $1,500.
The law specifies installation costs include: "expenditures for labor costs properly allocable to the onsite preparation, assembly, or original installation of the property."

The tax credit for solar water heaters, solar panels, geothermal heat pumps, wind energy systems, and fuel cells is 30% of the total cost (product + installation), with no upper limit.
The law specifies installation costs include: "labor costs properly allocable to the onsite preparation, assembly, or original installation of the property and for piping or wiring to interconnect such property to the home."

Installation costs are NOT covered by the tax credit for:
* Windows
* Doors
* Insulation
* Roofs

HOWEVER,
The tax credit for windows, doors, insulation and roofs is for 30% of the cost of materials, up to $1,500.

Read more about federal tax credits for energy improvements. [<- updated March 6, 2009]

Looked into those tax credits awhile back and they only covered the upper end of the energy star requirement, and in the case of windows EXCEEDED the ES requirement. Read it carefully before you get too excited.

stillerguy - makes sense to me, thanks.

tolamapS said:stillerguy said: ...
Hope this makes sense.

Stillerguy, good post, thanks. However, your post did not answer one question I had. Are you a Stiller's fan?

Go Stillers! 6 and counting ...