Lessons Learned Take Two:
About two or three weeks ago, we conducted an energy audit at a home on Coral Way close to 37th Avenue. It was a condominium apartment about 800 sqft., 1 Br/1Ba on the 10th floor. They had a nice view facing north and can see much of the county over the horizon -- a 180-degree view-point. That's a definite advantage over a single-family home.
The homeowners, David & Taby, were happy to see us arrive wielding our high-tech equipment to test their home. We exchanged pleasantries and quickly began work. When we asked for the location of the air handler to get the info on it, the response on the location came from David. And Taby followed with a comment about the hot water heater being located in the same location adding that she doesn't think it works well. David responded saying it's fairly new so, nothing should be wrong with it. Taby then wanted to see what we had to say about it.
So, I asked her: "What issues were she facing?" She said her problem with the hot water heater was that it would not heat adequately when she was washing her hair. She stated further that after about 5 or so minutes the water would lose its heat. She estimates it takes her about 15 minutes to complete the job. Anyhow, David chimed in saying that a co-worker told him about instantaneous hot water heaters and proceeded to talk about how he could use it, etc. He suggested that this change may do the trick and shared the insight that his co-worker told him in how it would affect electric usage. I took it all in but I wanted to investigate it further. The reason can be read by a recent post.
After recording the specs on the hot water heater, I saw that it wasn't that old as David had said. And after close inspection I didn't see anything wrong with it. So, I wanted to find out more. I checked and found the distance from the hot water heater was less than 10 feet. And they don't typically run the washer or the dishwasher during a shower. So, why is it that the 30-gallon hot water heater fails to produce enough hot water for a hair wash?
They were intrigued by our investigation. Everyone piqued, trying to find out what the problem was. There shouldn't be any problem if the hot water heater is working properly. Anyhow, the heater is located under the air handler in a closet next to the front door in the hallway. The hallway is air conditioned and the closet door isn't sealed. So, some of the heat from the tank could be lost to the ambient cold air. But that doesn't explain away the ineffective system. All along, I knew what the likely problem was, but I wanted to include them in the investigation so they can learn from the experience.
We went into the bathroom and I looked at the showerhead and I couldn't find any visible ratings on it but I deduced that it may have a flow-rate of about 5 gallons per minute (gpm) based on what was mentioned earlier. Quickly calculating a 5 gpm flow-rate for a 30-gallon tank means that hot water (or lukewarm due to heat loss) stored in the tank means they have about 6 minutes of hot water available to them. They were astounded by the simplicity in the underlying cause of the problem. Neither would have known what the problem was and could have spent money fixing a perceived problem only to create another problem. This mis-application would have cost them more money:
A Titan N-10 tankless model would have cost them about $250 plus shipping, the install and the increased electric usage. All told, we estimated that they could have spent about $1500. When they could spend less than $250 to change the shower head and wrap the hot water with a thermal blanket. Purchasing a 2 gpm shower head would give her the 15 minute heated water. The thermal blanket can keep it hotter longer so that mixing could further add longevity to the shower.
Sometimes advice can lead to wrong results even if it was well meant. This was simply a well meant shortcoming. Your best bet is to hire a pro -- they have the experience and training to look for these things. ;-) Besides, they are well oriented in energy efficient principles. "One man's cure can be another man's curse."