Tank type electric water heaters—hard to beat.

Super Insulated Water Heater

Me in my water heater

Everyone that knows me, knows I spend a lot of time in my basement playing with my water heater.

I have always been skeptical of the claims made about different types of water heaters and I have never had anything more than anecdote to sort out any truth of these claims.

About 6 months ago I bought an electric meter to install on the water heater so I could keep track of exactly how much electricity it uses.  This takes some of the extrapolation and guessing out of equation.

What I am writing here in no way clarifies everything but it clearly demonstrates the whole topic needs to be revisited by people with more money and testing facilities than I have.

Some of this inquiry is in answer to advertising by on-demand water heater manufacturers that would have us belief tankless-type heaters are god’s gift to water heaters and that tank type heaters are no longer a viable way to heat water. 

There are lots of pros and cons to both types.

It is my premise, if water heaters came with a LOT more insulation than is currently required, they can remain competitive in cost to operate and certainly in cost to install. 

The initial costs and maintenance costs associated with tankless water heaters is still considerably higher than tank type heaters–and lets face it, they are as complicated as under the hood of your car.

An interesting thing happens when you install an electric meter on your water heater.  It becomes very difficult to use hot water “normally.” This is because of the nagging little voice in the back of your head that questions whether you are wasting hot water while you are doing the dishes, doing the laundry, taking a shower or washing the cow.  That said, the ratio should remain similar even if the numbers end up somewhat higher.

Meaningful numbers can still be found when comparing operating costs of an off-the-shelf heater compared to one that is super-insulated.

About two months ago, my heater died.  When I replaced it, I replaced it with another tank type heater that was 15 gallons smaller than the previous heater.  I decided I would monitor costs for a period of time prior to super insulating it.  The tank comes insulated to R-13.  I would ultimately insulate the tank to R-40.

My installation is further complicated by a re-circulation loop.  I also wanted to determine the operating costs of the loop.  Just how much did it add to water heater operating costs?  In addition I wanted to see performance differences of keeping the tank and loop at 135° F and 120° F.  I suspect I could have gotten better numbers if I monitored for a whole year or several years, but I was merely looking for hints of the truth.

Super Insulated Water Heater

Insulated to R-40

At 135° F, the operating costs of the loop resulted in an additional 15 cents per day.  The loop operated for 15 minutes an hour between 6am and 10 pm. 

The loop with super insulated lines and tank also results in having a larger volume of hot water sitting in the tank waiting to be used.  The hot water circulating to the bottom of the tank mixes with the incoming cold water reducing the amount of time it takes to bring all the water up to the set temperature. 

If power is lost, I still have a tank full of hot water for a couple of days.  With the tankless you immediately have nothing.

My loop is a thermosiphon loop (no pump) and has a timer with an electronic valve to control how much it operates.  The loop to the kitchen and back to the water heater is approximately 88 feet and insulated to R-20.  I consider this cost per day to operate the loop as insignificant.  The cost is mostly offset by the savings related to not wasting water.

After insulating the tank to R-40, the per day costs to heat water to 135° F averages 92 cents per day.  Prior to insulating the tank, the average daily cost was about $1.20.  This is approximately a savings of 24%.  This results in a payback on the $152.00 cost to install the R-40 insulation of 1-3/4 years.  Over the 20 year life of the water heater (typical of my area) that could be a savings, at current electrical rates, of $2060.00.  This is the cost of more than 5 water heaters based on the $400.00 cost of my recent water heater purchase. 

I know of no comparable way to get this kind of savings with a tankless water heater and of course initial costs are much higher with the tankless.  Maintenance costs over 20 years is going to be close to the savings of the super-insulated tank type heater.  Keep in mind that estimates of cost to operate tankless water heaters do not include increased costs to maintain re-circulation loops.

I realize no one is likely to do their water heaters what I did to mine to achieve these numbers. 

This exercise is to expose the silliness of what we currently require of manufacturers. 

Manufacturers could certainly add insulation to R-40 (or higher) at the time of construction much cheaper than I can do it in the field.  This seems like a no brainer if we are serious about conserving energy. Of course this only applies to electric water heaters that can be heavily insulated at the sides, top and bottom.

Another factor that comes into play, is that the size of the tank can be much smaller, which even further reduces annual costs to operate the heater. It also deals with possible problems with replacing larger heaters that would be bigger if insulated to R-40.  There is no reason standby-costs on a tank-type water heaters can’t be brought under 50 cents a day–probably under 30 cents a day if the tank is 40 gallons or less.  With a super insulated tank, a 40 gallon tank should be more than adequate for a family of four.

When are we going to start requiring manufacturers to install more insulation on their heaters?

Temperature behind the insulation

The temperature of the tank behind the added insulation is 100° F

Charles Buell, Real Estate Inspections in Seattle

Vented Crawl Spaces in the Northwest

I wish vented crawl spaces would just go away.

Wood Decay/Fungal Rot

Wood Decay/Fungal Rot

We could then turn the entire conversation into a discussion about conditioned crawl spaces. It is still the norm to have vented crawl spaces in the Northwest.  New vented crawl spaces are being built every day, in numbers much greater than conditioned ones.

It is important to understand how crawl spaces work because we are going to continue seeing them in older construction, as well as in newer construction.

If you live, or have lived, in other parts of the country, some of this may seem counter intuitive.  One could create problems in the crawl spaces of Minnesota or Georgia if one did some of the things we have to do in the Northwest. 

The numbers one puts in the equations are different, but the science is the same.

Getting just a few things right will allow a crawl space to behave itself and manage moisture conditions adequately.

The crawl space should be constructed such that vents can be installed on at least 3 sides.  A good vapor retarder on the crawl space floor is essential to the success of most crawl spaces. 

It would be nice if all the seams of the plastic were welded together and all the edges were caulked/sealed to the foundation.  However this degree of tightness is not necessary.  I have seen crawl spaces with floating vapor barriers and normal wood moisture content levels.  Adequate passive ventilation will remove the amount of vapor that finds its way around the seams of the vapor retarder. The building codes dictate how much ventilation is to be installed around the perimeter of the crawl space.

Crawl spaces that only allow for the installation of vents on one side, or two sides, may require a means of moving air through areas of poor circulation.  This can be accomplished with vents at the open side that are ducted to the poorly vented areas.  We then install a power vent fan in the duct to move the air mechanically.

Power vent

Crawl Space Power Vent

It is unusual to see crawl spaces that need mechanical ventilation. It may be warranted in instances where enough passive ventilation cannot be installed. You certainly cannot fix a moisture issue in a normally vented crawl space with power ventilation.  You first  must address the moisture issue.

The purpose of crawl space vents is not to lower moisture levels created by flooding and plumbing leaks. 

The purpose of venting is to deal with minor amounts of soil moisture vapor and to lower humidity that builds up seasonally.

We must understand the science of Northwest crawl space moisture.

On a recent inspection there was a power vent installed.  Operation of the fan was based on crawl space temperature.  It was set to run at 50°F.  It was running at the time of inspection. The unit’s built-in sensor shuts the unit off at 40°F.  This particular system operated under the assumption that the higher the temperature, the more the fan needed to run. 

This is exactly opposite the science.

In the summer we have moderate relative humidity and higher temperature than we do in winter.  In winter, we have very high humidity with lower temperature. 

70°F at 65% humidity would be normal in summer, while 37°F at 80% humidity would be normal in winter. 

While humidity in summer is lower than in winter, the “actual amount” of moisture in the air is much higher in summer.  Warm air can contain more moisture.

In summer, when that warm moist air enters the crawl space, it mixes with the warm wet crawl space air to effectively raise humidity levels in the space as it passes through.  This elevated humidity in turn raises wood moisture content of the crawl space framing.

In winter, the air outside the crawl space has very high humidity but at low temperature.  When we bring that wet cold air into the crawl space, it mixes with the warm moist crawl space air and effectively lowers the humidity as the air passes out of the space. Wood moisture content of the crawl space framing lowers as humidity drops.

Crawl space wood moisture content goes up and down with the seasons.

If we do not recognize this, plan for it and build for it–bad things are likely to happen. A few of those “bad things” might be mold, rot and wood destroying insects.

ANOBIID BEETLES:

When we do not control moisture levels in the crawl space, it becomes vulnerable to wood boring Anobiid Beetles. 

This is true even if there are no other uncontrolled moisture sources.  Anobiid Beetles prefer wood moisture content between 13% and 18% so it is important to keep wood moisture content below 13% in the summer.  A properly vented crawl space can do that.

When I find moisture levels around 13% in summer, I generally do not worry about it as much because I know moisture levels will drop below that in winter.

If I find moisture levels at 13% in winter, it is more of a concern because wood moisture content will be higher in  summer.  This is when the crawl space is vulnerable to infestation by Anobiid Beetles.  Moisture levels must be brought under control.

Anobiid Beetle exit holes

Some climates that are dry in the winter close their crawl space vents in the winter. Closing vents in winter in the Northwest would result in increasing moisture levels in the space year round.  

Wood moisture content will increase if the power vent is allowed to run all summer.  In the winter, when it is colder, the fan will shut down.  We will not lower the levels that built up in summer–levels that increased more than normal because of the fan. If you have a situation where power venting is necessary, the fan should run in winter and not in summer. 

A good vapor retarder on the crawl space floor and repairs to all bulk water issues is assumed.

There are vendors in the Northwest that would have consumers believe that no crawl space can be successfully vented.  This likely has more to support product sales than science.

Charles Buell, Real Estate Inspections in Seattle and the Great Northwest

 

The cat that wanted out!

I would never try to escape

Inspectors frequently have to deal with pets left at home at the time of inspection.

I really appreciate it when they are either gone or corralled somewhere in the house.

On a recent inspection the agent had warned me the cat would try to escape and sure enough, as soon at the door opened a crack the cat launched itself at the daylight.

I have seen lots of pets that wanted out, but this one was SERIOUS about it.

The cat was shooed away from the door and we all got inside.  The inspection went without event except for one short term escape accomplished by the cat.

At the end of the inspection, the agents all left and the inspection of the exterior continued.  This is not my normal protocol but this was a large apartment building and we saved the exterior for last.

The cat’s unit was on the 3rd floor, end unit.  The walkway ended at the entryway door and the bedroom window was located just past the end of the walkway guard railing.  As I approached the end of the walkway the cat launched itself onto the window screen and started clawing at the screen with a vengeance. 

Don't leave pets at the inspection

The damaged screen

The screen came undone along the edge and was ripped open vertically.

I tried to push the cat off the screen and into the room but the cat was having none of that and just clung and scratched at the screen even harder.

Eventually I was able to reach between the cat and the screen and pull the window shut– successfully bumping kitty off the screen and into the room.

The cat was not aware of it, but I probably kept it from using up one of its nine lives by saving it from a 3 story fall to the concrete below.

But I want OUT!

I called the listing agent to let the cat’s owner know about the damaged screen and that the window was no longer  adequate to prevent escape of the beast.

Sometimes cats just want out.

Please don’t leave your pets for the inspector to deal with.

Charles Buell, Real Estate Inspections in Seattle