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Many people who are looking for ways to save on their gas/electrical bills are visiting my website, but some of them express doubts if this is actually working...
Here is just one example:
Hi Ed,
As everyone else visiting your web pages, I would like to save on heating and cooling costs :-) (no surprise, eh?)
I have a couple of questions for you, and even with the fact that I would have to pay you double or triple what you ask for, this will not be a problem! What it is important to me is to understand the RATIONAL behind your answers... I am a technical person in nature, so understanding what is going on under the hood is what makes me feel comfortable to do any changes.
Anyway, let me know if you can answer me the following:
- Do you really save energy controlling the vents in unused rooms or not?
- If it is true, then when closing too many vents, can I damage my heater/AC unit? How do I know my unit will be safe with any changes you propose?
- So what are the magic changes I have to perform to my system in order to save $$?
My house is ~2700sq feet with finished basement, and from what I can gather from information on your web site, it seems that I own a "high efficiency condensing furnace"..
Let me know how to proceed... Waiting to hear from you soon!
Cheers
EB
So, before I go any further let’s take a look at what the others are telling you about this issue on the web:
associatedcontent.com
Save Energy and Money by Closing Unused Rooms
Close Up Unused Rooms – Registers.
All registers in an unused room should be closed and covered to reduce energy costs and reduce waste. Be sure to do the same thing to air vents or registers that both push air into the room and take it out. Baseboard heaters can also be turned off and covered, though this is a bit more difficult.
To safely cover registers and air vents, first be sure to close them completely. There are commercial register covers that can be used. Some are more complex things you screw into the wall, but there are also magnetic sheets that can be attached directly to the metal fixture.
ehow.com
Close all registers and heating ducts in the room. Close both intake and outflow vents. Cover these registers with purchased covers that screw into the wall, magnetic sheets made especially for this purpose, or any non-flammable material that can block any air leakage more effectively.
So, these two websites are recommending you to close vents and save!
However, at the same time the other two are telling you otherwise:
gardenweb.com
Question:
Does it save money on your utility bill, if you close the vents & doors on rooms that you don't use when using central gas heating?
Answer# 1:
I would say no because the furnace is turned off & on by thermostat which also control how long it runs. Which means it runs until satisfied at the location it mount (where hangs).
Answer# 2:
If you close a supply vent, and room has leak windows or air infiltration problem. This could create (not say it will) a negative pressure in room- allowing the return to suck threw cold air threw leak windows, walls , ceilings which if was real bad cold increase heat cost a little.
It is better to have air return and supply open in all rooms not be block by furniture to be balanced in positive and negative air pressure.
In my opinion it bad to block off vents, it will not make the furnace run any less.
Every furnace instruction book will tell you what the temperature rise across the heat exchanger should be.
If you turn off to many heat runs then you could get too much temperature rise and damage your furnace by over heating it.
If your temperature on return is 70 then the hot air coming out should not be more then about 140 degrees on most furnaces.
Feedback:
Thank you so much for answering my question. I have read & heard that in order to lower your electric bill; one should close off unused rooms, as well as close the vents to those rooms. Your answers have helped me to understand why this is not such a good idea.
Well, it is a very common practice: you are thinking that you are getting some good professional advice, but instead it is just a narrow-versioned opinion from the people who never looked into this issue at all.
consumerenergycenter.org
CLOSING OFF VENTS AND ROOMS TO SAVE ENERGY
Years ago, people would save energy use by closing off portions of their homes that were not being used. This occurred usually in the winter when people would huddle around a fireplace or wood stove and close off other non-heated rooms.
Some people still think that by closing off an unused room and its register saves energy. Some people close off all registers except for the one in the living room.
While this may have worked with older, non-insulated homes, it doesn't work with today's energy systems - forced air heating and cooling systems.
According to a 2003 study by the Lawrence Berkeley National Laboratory:
"Closing registers in forced-air heating systems and leaving some rooms in a house unconditioned has been suggested as a method of quickly saving energy for California consumers. This study combined laboratory measurements of the changes in duct leakage as registers are closed together with modeling techniques to estimate the changes in energy use attributed to closing registers.
"The results of this study showed that register closing led to increased energy use for a typical California house over a wide combination of climate, duct leakage, and number of closed registers. The reduction in building thermal loads due to conditioning only a part of the house was offset by increased duct system losses, mostly due to increased duct leakage. Therefore, the register closing technique is not recommended as a viable energy saving strategy for California houses with ducts located outside conditioned space.
"The energy penalty associated with the register closing technique was found to be minimized if registers farthest from the air handler are closed first because this tends to only affect the pressures and air leakage for the closed off branch. Closing registers nearer the air handler tends to increase the pressures and air leakage for the whole system.
"Closing too many registers (more than 60%) is not recommended because the added flow resistance severely restricts the air flow though the system leading to safety concerns. For example, furnaces may operate on the high-limit switch and cooling systems may suffer from frozen coils."
www.energy.ca.gov
Final Report for Profitability, Quality and Risk Reduction through Energy Efficiency (pdf file)
Prepared For: California Energy Commission Public Interest Energy Research Program
Prepared By: Building Industry Institute (312 pages doc.)
Conclusion
One of the most common practices in California production home building is to place the supply registers in the ceiling and to locate the return in a hallway ceiling. While cost-effective for the builder, the CFD results show this to be the least energy efficient design, particularly in a cooling dominated climate zone. This practice should be discouraged and one of the alternative methods below should be followed. In deciding supply register placement, heating versus cooling dominance needs to be considered:
- In a cooling dominant case, the in-wall supply registers with the ceiling return provide the best energy performance, whether the return is in the ceiling or the low-wall. If the ceiling return is used, there is a small positive impact when heating is considered. The low-wall return also provides improved energy performance.
- In a heating dominant situation, the ceiling register with low-wall return provided the best energy performance. Depending on the amount of required cooling, this design can have a negative impact on energy use.
- The ceiling register/wall return is a cost-effective compromise in a situation where heating and cooling needs are balanced.
What you just read are two diametrically different opinions, in one case supported by the Lawrence Berkeley National Laboratory study and the opposite opinion supported by Building Industry Institute!
So, who is right or who is wrong in this debate? Ironically both! One is telling you: close everything you can think of and save! Another: do not touch anything!!!
However, the truth, as usual, lies somewhere in the middle:
Yes, you cannot close all the supply registers you want to and save, without destroying your furnace and/or AC, unless you do it somehow different!
Yes, you cannot close all the return grills you want and save, unless you do it the other way!
When a few years ago I’ve conducted a test in my house, I’ve found out that as a result instead of 18 minutes my furnace was working only 15 that gave me a 16.7% of saving (the outside temperature at the time was 29*F, Ambient temperature was 68*F). Since then I have improved my system of air distribution even more and got solid 20% of saving! My furnace and AC are Carrier brand 10 years old, and they are working just like Swiss watches! (Sorry I know it's not patriotic).
If you would like to find out how I did it you can purchase an instant access to both pages at the discount price of only $4.43.
Here is just one more example on how people are getting an idea of saving some money on their utility bills, but looking for an advice on the so-called Forum websites where so-called experts happy to help them out:
Question
Saving money on AC?
We're trying to save money on our air conditioning bill. One thing that we've done that's helped significantly is changing the (4) air filters on our return vents from MERV 10 to MERV 6.
Another thing we've been doing is closing off rooms that aren't in use, like our guest room. My question is does closing off room (shutting the vents) really save money? Also, what happens if that room has a return? Should we close that too?
Thanks,
Kelly
Answer 1
It saves no money closing vents & rooms off. The system is designed for X amount of airflow. If the HVAC Company did not calculate in those other rooms, it would not have put a system designed for the size of your home into service. Do yourself a favor, and just keep those rooms open to allow the whole house to stay cool. Basically saying, you are actually causing more problems than it is worth, and no money is being saved.
Does this guy right? Yes, he is right, because if you just close a few vents here and there you will choke the system and save nothing!
Does this guy wrong? Of course, he is wrong because he doesn't see beyond his nose! If everyone around were just like him, we still would be riding horses!
Answer 2
If turn off your AC you'll save a lot money.
Follow-up
I'd love to, but at 95 degrees, with 70% humidity I'll keep the AC on.
Answer 3
You could always run an extension cord to your neighbors!
Answer 4
I have the best suggestion: move to North Pole!
Above is just a bunch of idiots happy that they can read and write...
Answer 5
I have tried the vent closing before, and as mentioned, it doesn't work. The new thermostat I bought has helped. I keep it at 79 during the day.
I limit using the stove as much as possible and have sun filtering blinds & curtains in most of my windows.
At least the last one has already tried something, but with the negative result! Does it mean that he did it right? Of course not!
In order to save, you have to modify your ductwork and you have to add some heat runs and returns. If you are willing to do that, if you want to know how it may work for you, info on the paid pages will lead you trough step-by-step instructions to the saving you are looking for!
So, if you would like to save money on your utility bill please contact me from this page, describe your house and HVAC system and I'll tell you if I'm able to help you or not.
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