Before central air conditioning, evaporative coolers, or swamp coolers, helped keep homeowners cool. Many older homes in Phoenix had no central air when they were first built and remnants of the original swamp cooler are still visible in a home, such as upducts or a cap in the roof where the evap cooler used to be located.  The advantage of using the evap cooler are lower energy bills because the evap cooler only uses a large blower motor to blow air over a filter drenched in water. Many homeowners who have evap coolers try to hold out on using their AC as long as possible but when the temperature rises above 100 degrees in Phoenix, the evaporative cooling just can't cut it.

Because the evap coolers are so much less to operate, many homeowners figure that they it's cheaper to run the evap cooler in May and June and then switch to central air for July and August.  How much does that method really save though?  As energy auditors and home performance contractors we have seen dozens of homeowners faced with this situation.  The short answer is that homeowners will save more money (and be more comfortable) by capping and sealing the evap duct and just using their central AC in the summer if the ducts are sealed, the home is sealed from the attic and insulation is up to R-38.

Some homeowners, we are able to cap and seal the evap duct connections a perform a proper sealing and insulating of the attic. Some homeowners have a tougher time letting go as it is like parting ways with a favorite tee-shirt.  The homes that have the evap cooler connection still in place will have minimal change in their bill, even if a duct seal, air seal and insulation upgrade is done!  The homeowners that do cut ties with their evap cooler, have seen a great reduction in the following energy bills as we have heard and followed up with many of our customers.

Surprised? When our energy auditors measure the duct leakage on a home with an existing evap cooler connection, that leakage is sky high! The dampers on evap duct systems are ineffective and a major source of leakage.  The damper will cause a 4 ton AC unit to put out only 3.5 tons of air.  Add to that the air leakage and heat gain from the upducts located in each room and you have a recipe for high energy bills.  There are replacement dampers for evap ducts and some are actually pretty good.  The problem is finding an AC contractor who can source and install them.  If duct sealing is done with the evap connections still in place for future use, the major source of leakage is still present after the work is done, which is why energy bills will not do down that much.  When a home is properly sealed, the ductwork is tight and a thick insulation blanket is keeping all the conditioned air inside the home... bills go down and the cost savings begins!

Let me start right off the bat by saying that spray foam insulation is a great product, especially in Arizona. There, end of discussion...? Well, not really, there are actually some considerations that should be weighted-in when considering spray foam insulation.  

The first and biggest is the cost. Spray foam insulation is about $4 per sq ft, and that is not just your attic roof space is about 30% more square footage than out attic floor area, that should be taken into account when budgeting. So if your home is 2,100 sq ft single level, your attic roof slope eligible for spray foam would be around ( 2,100 x 30%) + 2,100 = 2,730 sq ft with a cost for adding spray foam of 2,730 x $4 = $10,920! You can get a small solar panel system for that cost or take a nice vacation to Europe... Europe or spray foam in the attic? Spray foam is definitely an investment and we encourage our customers to do it if it meets our 3 step cost benefit analysis listed below.

1. Are there other energy saving improvements that will give a better bang-for-my-buck?
2. What other energy saving improvements will give me the same comfort results as spray foam?
3. What is the lifetime value of spray foam vs other energy saving improvements?

Below is a summary table of other energy saving recommendations common for Phoenix homes and their associated cost savings, comfort impacts and lifetime value considerations... all three cost-benefit analysis in one location.  The table shows estimated savings on an average 2,100 sq ft home in Phoenix.  The cost effectiveness is rated on a scale of 1 to 10, with 10 being the highest rating.  The Average ROI is found by taking the savings / cost, with the higher numbers giving quicker paybacks.  The Comfort Factor is also on a scale of 1 to 10 with 10 being the highest rating and having the biggest comfort impact. The Lifetime Value column takes into account the useful lifetime of the upgrade. For example, a pool pump's lifetime is 10 years, shade screens have a lifetime of 10 years and insulation has a lifetime of 25 years. Upgrades like duct work sealing, insulation and air sealing have lifetimes capped at 25 years. The higher the number, the better for the Savings to Investment Ratio.  Spray foam was estimated to have a savings of $300 a year, over a generous 50 year lifespan with a cost of $11,000.

By looking into all the alternatives, you can see a typical home has multiple options to choose from that are both more cost effective and can fix temperature fluctuations in the home. Yes, it is true that spray foam will put less wear on an air handler located in the attic but if that air handler is starved for air because of bad duct design or leakage, it's still going to be overworked no matter what the temperature is in the attic.

By having an energy auditor assess your home, you can answer how much money will I really save from spray foam? Let's be honest, if you have a spray foam contractor and an energy auditor to your home and ask them both the same question, who do you think will give you the more accurate answer? The sales guy who does zero testing on your home and whose visual inspection and estimates are based on what the spray foam manufacturer say (think estimated MPG vs actual MPG), or an energy auditor who measures actual leakage, heat gain and room pressures and runs your home measurements through a software modeling program to explore all the options indiscriminately. 

One of my favorite facts for homes in Phoenix is the heat gain chart published by SRP which shows that only a minor portion of heat gain in our homes comes from the attic.  Simply put, if a spray foam rep sounds like he is over promising savings, they probably are.

Spray foam is often touted as the end-all-be-all comfort solution if you are experience hot and cold rooms. This reminds me of the radiant barrier days, where energy-saving happy salesman would go around claiming 50% total utility bill reduction from radiant barrier alone! Spray foam definitely has a heavy hand combating comfort issues, but is shortsighted in that it is missing duct design and duct sizing in the picture.  Even if your attic is no more than 20 degrees from the inside of the house with spray foam, if your 5 ton HVAC unit is only putting out 4 tons of air, you are still going to have airflow and comfort problems.  Until I see spray foam companies start talking about duct design and the world of airflow issues, I'm putting them in the slap-happy savings category penalty box.

Costly Mistake #1 - Keeping the interior doors closed

Have you ever noticed?

1. Doors that slam shut by themselves whenever the air turns on?

2. A rush of air felt under a closed interior door when the air is on?

3. A resistance felt like someone is pushing back when you open an interior door and the air is on?

4. Or an increase of allergic symptoms when at home?

If you answered “yes” to any of the questions above, you likely have high room pressures. Isn’t a high room pressure a good thing? Actually, no, and the answer is because the air the goes into the room becomes trapped behind closed doors and cannot circulate back to the return, making your AC system work harder? How much harder? Studies in Phoenix homes have shown a 15% reduction in the heating and cooling bill by installing room pressure relief measures.  The takeaway… keep your doors open.

Resources:

Is It Best To Close Bedroom Doors At Night?

http://www.greenintegrateddesign.com/blog/should-you-leave-your-interior-doors-open-or-closed

Watch our video on closing interior doors at the link below.

http://www2.abc15.com/web/knxv/lifestyle/sonoran-living/sl-sponsors/green-id-shares-tips-to-conserve-energy-

Costly Mistake #2 – Using pleated filters

Pleated filters are promoted as allergen-reducing and dust-reducing filters at Home Depot and Lowes, but it is at the expense of a shorten life of your air conditioner.  Using pleated filters cause your AC unit to work much harder than it needs to because is it so much harder for the unit to “breath” properly. Imagine breathing through only 1 straw, we would run out of breath pretty quickly and that is what is happening to your AC unit with the pleated filters.  Not enough air is allowed to pass through the filter, so the capacity is reduced, the unit becomes stressed and it sounds like a wind tunnel every time the unit kicks on.  Us energy auditors like the cheap throw away filters, or a 4” HEPA filter which provides even better filtration but without sacrificing airflow.

Resources:

See a video of us showing three different options for air filters at the link below.

http://www.abc15.com/lifestyle/sonoran-living/sl-sponsors/green-id-explains-how-to-save-money-and-energy-with-he-proper-air-filter-in-your-home-

Costly Mistake #3 – Going solar before looking at efficiency.

Did you know making energy efficiency improvements to your home is 5 times more cost effective compared to going solar? That means that for every $1 you reduce your energy bill from energy efficiency upgrades like duct sealing, air sealing and insulation, you would spend 5 times more money making the same $1 reduction with solar.  It’s not that we don’t advocate for solar, it just makes sense to look at efficiency first and get the guts of the home up to par before going for the bling.

Costly Mistake #4 – Adding more insulation to your attic when it already has enough.

The cost savings for adding insulation to our attics has a point of diminishing returns. That is, at some depth of insulation, the cost savings we get for that extra depth dramatically starts to taper off and eventually levels out.  Is your home has R-19 insulation or less, you will ride the wave of great cost savings when going for extra insulation.  However, if your attic already has greater than R-19, you will still see benefits to adding insulation in your attic, but not as dramatically as before. Your money may be better spent on air balancing, shade screens or duct sealing depending on what the results are from a home energy audit.

Costly Mistake #5 – Failing to insulate the interior attic hatch

That 2x3 sheet of drywall has likely been left bare, void of insulation since your home was built. Heat always goes in the path of least resistance which would likely be the attic hatch.  By purchasing a 2” thick sheet of foam board and gluing 4-5 of them on top of the attic hatch, you will have stopped the flood of heat gain coming into your home through the attic hatch.

Looking for more energy savings ideas? Schedule a home energy with Arizona’s leader in personalized home performance, Green ID. We look forward to seeing how much money we can save you!

The advantages of going with a smaller, custom home builder in Arizona are many:

1.       Your floor plans, layout and design are all customized to your vision along with your architects.

2.       You get more bang for your buck than you would with a Pulte, Toll Brothers or publically traded builder.

3.       You have more control throughout the process.

However there are definitely disadvantages from an energy efficiency standpoint that may not be as obvious until you are already living in your home such as:

1.       Custom home builders many not have the resources to pull all the trades together to create an efficient home.  Yes the architect may be LEED certified but even LEED for Homes has deficiencies that an architect may not catch unless they are also BPI certified such as how insulation should be installed, not just how much you are getting.

2.       Because architects are working much more closer with homeowners, things that are best for efficiency may conflict with a homeowners desired.  For example, it is best to have subterranean returns in the Phoenix area with air handlers and ductwork located inside the home.  Unless your architect designs your home from day one, they may have to start from scratch because there was no space left to put the air handler or ductwork inside and the homeowner did not want to give up any livable space for an AC unit.

3.       A smaller builder (company is not publically traded) will likely sub his trades out which is a recipe for an efficiency disaster.  This was how homes were built for the last 100 years, you have the framer, electrician, HVAC, plumber and drywaller all working separately which is the main cause of inefficiencies in a home. 

Here is a punch list we created as a best practices list to prevent the source of inefficiencies that cause hot rooms, high utility bills and poor air quality from occurring. 

1.       Ask the general contractor to have a thermal barrier outlined for your home. Your home will already have an insulation barrier from the insulation contractor and a sheet rock barrier separating the conditioned space from the outside/ attic, but these two trades MUST be married together as one.  Are you planning to have coffered ceilings, arches, columns or plant shelves in your home? Make sure these areas are drywalled in to separate the attic from the interior walls of the house. Your thermal barrier will outline exactly where the boundary is defined.

2.       In two story homes with air handlers in the attic, make sure the HVAC contractor caps and seals off the duct chase to the first floor. If it is not capped and sealed you will have a large area of interior wall open to the attic.

3.       Put returns underground when the post-tension slab is being poured.  Traditionally returns are located in the ceiling and return ductwork is in the attic.  Our attics are dusty and reach temperatures greater than 150 degrees in the summer. Any ductwork located in the attic has to fight the heat from the attic plus if the ducts are leaky, your attic air will be mixing with the inside air of your house, making the AC unit work harder than it has to.

4.       Air handlers should also be located in closets inside the house.  Less heat = less stress on the units.  Yes, you will have to give up some livable space but your wallet will thank you when your neighbor is replacing their AC unit years before you have to.

5.       A HVAC sizing calculation called a Manual J calculation should be done to make sure your AC unit is sized properly for your home.  Bigger is not better in this case and you can get away with a smaller unit or a unit entirely, your architect is not cheating you, he is doing you a favor.

6.       Jump ducts or passive returns should be installed in every room. To help with air circulation.

7.       Stay away from fiberglass batt insulation. The rolled batts are not our friend here because they are extremely hard to install correctly. 

8.       All flex to collar connections should be sealed with mastic. All drywall gaps around the register boxes should be sealed shut.

9.       R-30 insulation in the attic is code and that is 10” of cellulose, not 8” as the insulation companies would have you believe.  R-38 insulation is Energy Star standard and is the level we recommend.

10.   West facing walls should have minimal windows or should be shaded by canopies or vegetation.  Good solar heat gain consideration should be taken into account by the architect. 

Just like car manufacturers come out with a design only car that is not meant to drive but for conceptualization and to push the engineering team, I wanted to see how many incandescent light bulbs it would take to actually heat a home... in the case that your heater goes out in the middle of winter and you find yourself with nothing but 500 illegal light bulbs and way too many power strips. 

Incandescent bulbs light bulbs only convert 10% of their energy use towards putting out actual light, the other 90% is wasted and converted to heat.  So let's say that a 60 watt light bulb puts out 54 watts of heat to a room per hour (60 x 90%). Here is a chart on how many kWh of heat is produced from different quantities of light bulbs

So to compare a furnace produces 75,000 BTU of energy per hr for a mid-size home or roughly 22 kWh of energy.  So we would only need between 500 light bulbs to produce the same amount of heat as our furnace is supplying.  At $1.50 per 60 watt bulb, it would cost an initial investment of $750 for 500 light bulbs.  When we hooked up all our power cords in a fire safe manner and plugged in our lamps, 500 light bulbs would draw 30 kWh, which is 8 kWh MORE than our 75,000 BTU furnace.  Plus our furnace would last about 20 years longer than our bulbs.  BUT if you are in a jam and have no heat, now you know how many bulbs you need to keep warm at night! 

It can seem like you can't go wrong with solar hot water heaters. Electric hot water heaters are the second biggest energy user in a home, always keeping the water hot and ready for your use... Did you catch that? Electric water heaters... not gas water heaters, your gas water heater is typically the largest gas appliance in a home if you have natural gas service. The thing is that in Arizona, our natural gas cost is relatively cheap compared to propane or even other cities like Chicago. Plus our winter climate does not demand a lot of natural gas usage from our furnaces... It simply does not get that cold during the winter in Phoenix.

You may get free hot water from a solar water heater but solar water heaters always have an electric water heater backup tank that WILL kick on if the water temperature doesn't reach it's 140 degree set point, which is happens more frequently than your rep may be aware of.  We have received lots of feedback from homeowners who had a solar hot water systems added to their existing gas water heater where their electric bills actually went up! 

By adding another water heater that is electric powered, your electricity use will unfortunately go up. It's an important distinction your solar hot water company rep may be blind to or may not disclose to you.

Solar hot water heaters use the sun to heat the water used for doing dishes, showers, laundry and in bathrooms and they are ideal for all electric homes with 3 or more occupants.  Solar tax credits and rebates make solar affordable for everyone but it may not be suitable for everyone.  Installing solar water heaters to homes may seem like a great idea but if your home uses natural gas for water heating, the old saying, "the grass is always greener on the other side" can apply to your water heater.  Do yourself a favor and stick with your existing gas water heater and put the money towards insulating your walls or sealing your ductwork instead.

If you are looking to upgrade your existing gas water heater, look into a tankless water heater instead. For larger families, a 20 gallon storage tank is available for reserve water.  Tankless water heaters are super efficient, only turning on when you turn on the hot water and instantly heating your water.