The Home Inspector

Reuben Saltzman is a second-generation home inspector with a passion for his work. Naturally, this blog is all about home inspections and home-related topics in the Twin Cities metro area. In addition to working at Structure Tech, he is also a licensed Truth-In-Sale of Housing Evaluator in Minneapolis, Saint Paul and several other cities.

Posts about Energy

My Beef With Fiberglass Batts

Posted by: Reuben Saltzman Updated: November 22, 2011 - 5:41 AM

Reuben's BeefFiberglass batts are a poor choice of insulation for most applications, yet this still seems to be the insulation of choice for most handy homeowners.  I'm been complaining about fiberglass batts for a while now, and for good reason.

Fiberglass batts are more expensive.  I stopped by the Maple Grove Home Depot and compared the prices of unfaced fiberglass batts, loose fill fiberglass, and cellulose.  Here's what I found:

$0.93 / square foot for R38 Fiberglass Batts

$0.56 / square foot for R38 Loose Fill Fiberglass

$0.30 / square foot for R38 Cellulose

Price Tag at Home DepotSide note:   Comparing prices at Home Depot was a pain in the butt.  Are they doing this on purpose?  The sign on the fiberglass batts said "That's only $0.93 sq. ft."   Yes, for R38... perfect.  But then the sign on a bag of loose fill fiberglass says "That's only $0.51 sq. ft."  FOR WHAT?  You have to get a calculator to figure out this is for R30.  What really drove me nuts was the sign for a bag of cellulose insulation, which said "That's only $0.15 sq. ft."  Again, FOR WHAT?  I got out my calculator, and determined that they're quoting the price for R19.  How are consumers supposed to make any reasonable comparisons when the three different prices per square foot are for three different depths?  These signs are worse than useless, they're misleading.

Fiberglass batts take more time to install. To be installed properly, fiberglass batts need to be painstakingly cut to fit the exact size of the space that they're supposed to fill.  Here are a few examples:

  • A 2x6 wall that has electrical wire running perpendicular to the studs;  should you push the insulation in front of or behind the wire, leaving a void in the insulation?  No.  You would need to cut the batt so it gets installed above and below the wire.  The images below show the original photo on the left, and the photo with a thermal image overlay on the right.  As you might guess, the red areas are warm.

Thermal image of fiberglass batts

  • A 2x6 wall with electrical outlet boxes; should you stuff the insulation around it, leaving nasty gaps around the box?  No.  You would need to cut out a rectangle in the batt so it fits around the outlet box without being compressed, and you would need to install a thin piece of fiberglass behind the outlet box.

Poorly installed fiberglass batt in wall

  • An attic with a bazillion electrical boxes, wires, pipes, truss chords, etc...; should you stuff the insulation around all of these obstructions, significantly reducing the insulating value?  No.  You would need to make a bazillion cuts and fits in the fiberglass batts to fill all of the gaps and voids.

The alternative to making all of these cuts and fits is to use something that fills in every little gap and void, such as loose fill fiberglass or cellulose in the attic, dense pack cellulose in walls, and spray foam at rim joists.  These methods take far less time.

Fiberglass batts are extremely difficult to install properly. As you read through the examples above, you were probably wondering who would ever take the time to actually do all of these things.  My experience has told me no one. I can't say fiberglass batts are impossible to install properly... but I have yet to find fiberglass batts installed properly in an attic.  All of the little voids that are left in fiberglass insulation equate to an exponential level of heat loss.  The photos below came from a five-year-old custom built home in Edina that I inspected.

Poorly installed fiberglass batts Poorly installed fiberglass batts 2 Poorly installed fiberglass batts 3 Poorly installed fiberglass batts 4

Fiberglass batts are itchy. I can touch the stuff with my hands and I'm fine, but once that stuff gets on my forearms, it's bad news.  My skin gets red, bumpy, and itchy.  Even if you're just walking on it, the fibers get released in to the air and they float for a long time.  Your skin doesn't even need to make direct contact with it to be affected.  This makes fiberglass nasty stuff to work with or be around.

So why are fiberglass batts still used today? For small jobs, such as re-insulating a wall or two, it might not make sense to hire an insulation contractor to fill the walls with dense pack cellulose, and it's not cheap to have spray foam installed.  As for attics, again, there is no special equipment needed to install fiberglass batts.  To blow loose fill fiberglass or cellulose, a huge insulation blower and hoses are needed, so it turns in to a fairly large project.  It's far easier to buy a few rolls of insulation at the store, drive 'em home in your car, and roll them out in the attic.

If you have an upcoming insulation project, I suggest using something other than fiberglass batts.  On Saturday I'll post a blog discussing all of the alternatives to fiberglass batts.

Reuben Saltzman, Structure Tech Home Inspections - Email - Edina Home Inspections


My beef with tankless water heaters

Posted by: Reuben Saltzman Updated: October 18, 2011 - 5:05 AM

Reuben's BeefTankless water heaters are sexy.  They take up less floor space, they provide an endless flow of hot water, they're environmentally conscious... and they're really expensive.   If you enjoy showing off your home's mechanical equipment to your friends or you're in to being green at any cost, get a tankless water heater. On the other hand, if you're in to saving dough, doughn't buy a tankless water heater.

A tankless water heater will not save you money.

I stopped by my local big orange box the other day to check up on the latest sales pitch for tankless water heaters.  The brochure for tankless water heaters said they can save up to 25% in fuel costs.  That sounds great, but lets examine what that means. I spend about $12 per month for natural gas during the non-heating season, if I don't include my fixed fuel costs, such as the 'fuel delivery charge.'  This figure includes the gas for my water heater, clothes dryer, and oven.  Just for the sake of argument, lets also pretend that I don't have a family of four who uses the clothes dryer all the time, and I don't use the oven all the time.  We'll pretend that I spend the full $12 / month just  to keep a 50 gallon tank of water hot all the time.

Fuel savings

If I save 25%, I'll save $3/month, or $36/year, or $720 over a period of 20 years.  My standard 50 gallon water heater has a 12 year warranty, and so does the tankless water heater I looked at... but the life expectancy for a tankless water heater is apparently 20 years, so I'll give it the benefit of the doubt and assume it will last that long.

Sizing a tankless water heater

The brochure on tankless water heaters said I should buy the largest tankless water heater they make, based on the number of bathrooms I have in my house - three.   The particular model is the ECOH200DVN.  This unit boasts a 9.5 gallon per minute flow rate at a 35 degree rise in temperature.  With an average ground water temperature of 45 degrees here in Minnesota, that would give me... 80 degree water.  Ha!  That's useless.  To get 120 degree water, my flow rate would be reduced to 5.1 gallons per minute.  Maybe I'll need two water heaters. For the sake of argument, lets just say I only need one.  This unit retails at my local Home Depot for $1,427.00.

Installation costs

Plumbers charge a lot more money to install tankless water heaters, because they're a lot more work compared to traditional storage tank water heaters.  The water supply pipes will need to be re-routed, the venting will need to be completely redone, the unit will need to be mounted on a wall, an electrical outlet may need to be added, and the gas pipe may need to be re-done.  Just for fun, let's say you were able to find a plumber to do all of this for $1,000.   A traditional water heater might cost up to $500 in labor for replacement, so we'll assume you're only spending an extra $500 in labor for a tankless water heater.

The bottom line

A traditional 50 gallon water heater with a 12 year warranty retails for $559 at my local Home Depot.   I would spend an extra $868 to buy a tankless water heater, and at least an extra $500 in installation costs, making this unit cost at least $1,368 more than a traditional water heater.  I would spend at least $1,368 for the potential of saving $720 over a period of 20 years.  If I ever buy a tankless water heater, I won't be doing it because I'm hoping to save money.

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