Friday, November 11, 2011

Attic Ventilator Fans: The good, the bad, and the ugly!

It is common practice for homebuilders, roof specialists, and HVAC companies to tout the importance and benefits of attic ventilator fans. The argument, which seems to make a great deal of sense, is that by creating airflow in the attic (powered) the heat gains will drop dramatically, therefore reducing electric consumption for A/C units. Is this really the case? As with most things, there is not a clear “black and white” answer. The reality lies in the grey area that I have decided to study a bit.

Savannah Renovations conducts its business in and around Savannah, Georgia. We have a hot, humid climate to deal with most of the year. It is common during the summer for attic spaces to have temperatures in the 120 to 140 degree range and I have read that in some cases they can reach 160 degrees! The hot sun beats on the shingles conductively heating the roof deck, and then through radiant transfer, the air inside the attic space is heated to incredible temperatures. Most homes (especially newer ones) have the air handler which contains the cold coil that cools air and also removes humidity hence the need for the drip pan and drain on your home located in the attic as well…you can imagine what these temperatures do to your cooling bills.

The stage is set and many companies sell powered and solar ventilation fans touting that purchasing their equipment will save you thousands. The science seems sound and all us contractors rally behind it because it seems to be almost common sense. Pulling in air from the outside at 90 degrees and replacing the 130-degree air seems to be a no brainer.

Here are the real facts:

A study done by Danny S. Parker and John R. Sherwin from the Florida Solar Energy Center (FSEC) (1) Sheds some light on the actual benefits of attic ventilator fans. Their study of a single family home in Florida showed the fans (2 installed) reduced attic temperatures over 20 degrees and reduced air conditioning consumption by 6%. The downside of this is that the cost of the fans and installation made the return of investment very low taking almost 20 years to pay for itself.

In a more expansive study, John Tooley (Natural Florida Retrofit), and Bruce Davis from Alternative Energy Corporation's Applied Building Science Center, looked at the unintended consequences of the use of powered ventilators in attic spaces (2). Their study of eight homes found that the attic ventilators caused depressurization inside all the homes. This depressurization caused safety concerns. Specifically, they noted that a gas powered hot water heater was actually experiencing back draft issues causing normally vented gasses to be pulled into the home. In addition, there was the issue of loss air conditioned air; an average of 231 cubic foot of air per minute!

Does this mean that forced ventilation of your attic is a terrible idea? No, but care should be taken and hiring a qualified and knowledgeable professional to help choose the proper product and conduct the installation is important! This is a perfect place for me to mention Savannah Renovations as such a company.
In conclusion, there are benefits and consequences of installing attic ventilator fans. Here is a summary by bullet point of the most important:

Negative points to consider:

  • An electrically powered 1500cfm attic fan usues about 325 watts of electricity. In the Parker/Sherwin study their test fan used 284watts and generated 170watts of savings from reduced air conditioner use. Therefore, my opinion is that electrically powered fans are out of the question unless there is little or no insulation in the home. Solar ventilation fans use no electricity…nothing more to say about that.
  • Care must be taken in choosing the proper fan. Oversized (which is the norm) fans can cause depressurization, pulling air-conditioned air into the attic. They can also cause health and safety issues. Especially if you have gas powered appliances and utilities in your home. The Tooley/Davis study noted a story of a Colorado family who died from carbon monoxide poisoning when their attic fan caused their furnace to operate in back draft.

Positive points:

  • A properly installed attic fan should reduce the summer temperatures by about 20 degrees.
  • Attic fans reduce humidity in the attic area more than passive ventilation alone.
  • The above points result in a reduction in cooling bills (approximately 4-7% in my opinion), and increased longevity of air-conditioning units due to the decreased stress (less heat and humidity around the coil, air handler, ducting, etc.).
  • Solar powered units are the only way to go! They pull no parasitic energy from the grid, paying for themselves over the long term. Not only saving you money, but saving our environment as well.

Finally, I will reiterate a pervious point(s). Attic ventilator fans can be a positive addition to your homes energy system. However, hiring a knowledgeable professional to help with fan selection, location, and proper installation is critical to see actual savings and keep your family safe. I believe that Savannah Renovations is such a company. Give is a call or email to see how we can help you!

Robert F. Foy



Friday, May 20, 2011

LED lighting: Is it a cost effective, environmentally sound alternative?

Working with commercial customers over the years has given me the opportunity to take on projects that I would most likely not have had if I focused on residential alone. Recently, I have had the opportunity to complete a LED lighting upgrade that had enlightened me on the subject and my findings have been significant.

First, some background: This project took place at Goosefeathers Café in Savannah. The café has used rope lighting for years to accent and make their restaurant stand out, because it was off a very busy square downtown and close to other prominent and famous eateries. The lights are on 24 hours a day, seven says a week.

I brought up the idea of using LED lighting originally not because it would save electricity, but because the standard incandescent lights we were using were failing far too frequently. Rope lights (both LED and incandescent) run in sections of 18 to 42 inches and when there is a failure the entire section goes out. The incandescent usually start to loose sections in an 8 to 12 month period. Additionally, the café owner was purchasing the lights from one of the large box-type home improvement stores. This placed restrictions on lengths, and the lights were not repairable…once a section went out, the whole string had to be replaced!

Now that I have some real information and data to work with, I can say that LED lighting is definitely worth the investment! Real life experience and for comparative purposes, I am going to argue that the lights will last 1/3 of the lifecycle that the manufacturer suggests before this first sections start to fail.

Initial installation:
  • Installation costs of the incandescent lights are $1.87 per linear foot including all materials. Goosefeathers uses 300 linear foot for a total installation cost of $561.00
  • Savannah Renovations charged $3.26 per linear foot including all materials to install LED lighting. Total cost: $978.00

Operating costs…I used the power bill calculator at the Georgia Public Service Commission’s website ( ) to calculate the operating expenses of the lighting. Although these are not the exact rates and calculations used for a business of this type, the method of calculation is similar:

  • The incandescent lights we were using operated at 3watts per linear foot per hour. Again, at 300LF this totals 900 watts per hour used to operate the lights. Since the average month has 730 hours, the average power costs would be:
    • $93.24 per month during the summer
    • $83.83 per month during the winter
  • The new LED lighting purchased operates at .64watts per linear foot per hour; this totals 192 watts per hour to operate. Once more, using 730 hours per month (average), the power costs for LED rope light are:
    • $29.10 per month during the summer
    • $28.25 per month during the winter

Maintenance expenses: As previously stated, my real life experience tells me that (at least concerning incandescent) the lights will generally last 1/3 of what the manufacturer suggests before the first failures begin to occur. Since I do not have the actual experience with LED lighting, I will assume this lighting will react similarly. To get a good idea of average annual expense, I have chosen to use a 10-year period to assess maintenance costs. With this information and these assumptions, I feel the following hypothesis is accurate:

  • Most incandescent lighting manufacturers state a bulb life of 20 to 33k hours. My real life experience with the lights at the café show that in reality the period is more like six to ten thousand hours before the first sections start to fail. With the particular lights used here there are no repair options, so since the sections start to fail, the whole rope must be replaced. Rope sections average two to 48 foot in length. The average length used here is 18 linear foot. Repair generally costs a little more than initial install because the service is particular to a small section and the labor charges are higher.
  • The repair/replacement of sections is usually $2.25 per linear foot for the incandescent lighting including all materials.
  • Based on the realized historical lifespan, the entire lighting system will be replaced 8.85 times in a ten-year period.

  • The LED lights we purchased for the project at Goosefeathers Café state a 100k lifespan. If the LED lights follow the same lifespan as I have seen with incandescent lights, they should last approximately 35k hours.
  • Here is where the big difference in maintenance comes in: the LED lights purchased are repairable! This means, when a section goes out that section can be cut and replaced. There is no need to replace all the lights!
  • I estimate repair costs to be $3.50 per linear foot including all materials.
  • Based on my hypothesis, the entire lighting system will be replaced 2.5 times over a ten-year period.

Total of expenses over a ten-year period including initial installation, power usage, and maintenance costs:

INCANDECENT: $16,495.20 and 78,840kwh USED

LED: $7,039.00 and 16,819kwh USED


The results of my small study have surprised me. Incandescent lighting does have a significantly lower initial installation cost, but beyond that there is no comparison. LED lighting operates at such a low energy level and lasts so much longer there is little argument left. In this one case, the owners will save $9,456.20 in the next ten years compared to the previous ten! Not to mention the environmental impact…62,021kwh have been saved over this same period! That is 62,021,000 watt hours of electricity!!!

LED lighting is definitely cost effective and environmentally sound! Call or email Savannah Renovations today (912-675-5569) for a free estimate and consultation to see how we can help you save money and do your part to help protect the environment!

Thursday, March 24, 2011

Mortise Lock Repair

Mortise locks are common in homes from the Colonial, Federal, Victorian and Arts & Crafts periods. Dating from 1607 to the 1920’s (over three hundred years), these locks in various forms were widely used. There are many resources to replace these mechanisms when they fail; however, I have found that finding suitable parts that actually fit is difficult. To be honest, these mechanisms are fairly simple and repair can be done by just about anyone with a modest level of skill.

Removal: Removal of the mortise lock from the door is easy. Simply remove the two screws on the faceplate holding the mechanism in place.

Disassembly: The first step in the process is to find the machine screw that holds the cover plate in position and remove it. I am sure that there may be manufacturers that may have used a different (2, 3 or more screws) configuration, but I have never seen them differ from this:

Once the cover is removed, take note of the position of all the bolts, levers, and springs.

Take special care (and I speak from experience here!) to note the EXACT position of the retainer springs…and there will most likely be two of them. These springs are critical to smooth and proper operation.

This is also a good time to inspect the mechanism for damage and to note what repair actions should be taken. The most common reasons these mechanisms fail:
  • PAINT, PAINT, and did I mention PAINT? More often than not, at some point in history, someone painted over the mortise lock rendering it unusable. A simple cleaning of the parts in paint stripper and mineral spirits usually does the trick.
  • Broken springs. Suitable replacements can usually be found at a hardware store or online dealers abound.
Remove the springs first. In my example, there are three. Once the springs are removed the rest of the parts pretty much fall out so be careful. When you remove, the parts make sure to lay them out so you can remember how they go back.

Once the parts are cleaned, a liberal application of lubricant will help the unit operate smoothly. Do not use a spray (like WD-40) this stuff makes a mess and attracts dust/dirt. The best lubricants to use are Teflon, or graphite type lubricants. In this application, I would also accept the use a lithium based lubricant.

Reassembly is reverse of removal. Just be sure the leaf type retainer springs are placed exactly where they should be.

Test the operation of the cam, bolt, and latches before installing the mortise lock mechanism. You can use the door set and skeleton key to check that everything works.

Alternatively, if this seems a little difficult…Please give Savannah Renovations a call at 912-675-5569 and we will be right out to repair your mortise locks and have them working as good as new!