I am trying to quanitfy the energy savings that is generated by having clean furnace filters installed. the furnace filter manufacturers have good data regarding air quality but what does a dirty filter do to the performance of the furnace? 

Views: 354

Reply to This

Replies to This Discussion

To get the conversation going...

Let me start by saying I don't have a complete answer to your question but thought I would throw this out for discussion.

I welcome comments.

 

You can measure the performance difference of the blower between a system with a clean filter and a system with a dirty filter.The measurement will be precise for that one system given those specific filters at that point in time. But it would be hard to apply that to other systems. I don't know if that is of use to you. Also, that is only the blower. I have some thoughts on measuring the rest of the system but they are weak. See below.

 

In order to measure the blower performance you need some way of measuring the energy use of the system.

You could use an Amp meter (Fluke makes a good one) or an energy mgmt device like (e.g. TED  http://www.theenergydetective.com/).

Once you have the energy mgmt device in place, run the system* with the old filter and note the energy use.

Replace the filter and take a new measurement.

Subtracting those two measurements will give you the energy wasted due to the blower.

That should be pretty accurate.

I ran a similar test trying to determine the performance difference with a barometric bypass open vs closed. I ran this test because I suspected the bypass was setup incorrectly and eating to much energy. My test proved my theory with real data.

 

However, you still need to account for the energy wasted from the heating system.

I have no great ideas here but will suggest the following two ideas as a better than nothing solution. I have little confidence of the accuracy of either of these but it might be better than nothing for a ballpark number and it opens up the discussion.

 

1. Use a ratio of the good filter to bad filter energy use and the system rated efficiency to the "bad filter" efficiency.

ex. Blower used 1000 watts with good filter and 1200 watts with bad filter. Furnace is 95% efficient (per mfg).

good filter energy / Bad filter efficiency = good system efficiency /bad system efficiency (BSE)

1000w x 1200 w  = 95% x BSE   or BSE = 88%

 

2. Calculate the additional time that the system has to run due to the inefficiency. Then calculate the fuel cost of that additional time (based on mfg data).

If the system is moving 800 cfm with a clean filter and we calculate the blower is only about 83% efficient  (1000w/1200w), with a dirty filter then the system is pumping 664 cfm. To get the same total volume of air, the system with the dirty filter would need to run 20% more (664cfm x 120% = 800 cfm).

For calculation purposes, let's assume the cost to run the system is $1 per hr per mfg specs, and the system is running 10 hrs per day. It would thus cost an additional 2 hrs and thus $2 per day with the dirty filter.

 

Bonus option: Use both of the above methods and average them out.

 

Paul

RSS

Home Energy Pros

Home Energy Pros was founded by the developers of Home Energy Saver Pro (sponsored by the U.S. Department of Energy,) and brought to you in partnership with Home Energy magazine.

Latest Activity

Brian Clavette added a discussion to the group Energy Auditing Equipment for Sale, Trade or to Purchase
Thumbnail

FLIR i-7 thermal imaging camera

Hi,I have a very lightly used FLIR 1-7 for sale.   i-7, serial # 60101-4267.  Full hard case and…See More
5 hours ago
Don Fitchett commented on Home Energy Magazine's blog post At Home with the Internet of Annoying Things
"True, for the smart consumer, the power savings should offset the additional power usage. For the…"
7 hours ago
Michael Dunseith posted an event

BPI Exams - All at Green Jobs Training Center

March 2, 2015 at 10am to March 31, 2015 at 2pm
Green Jobs Training Center is currently providing written and field exams for all of BPI…See More
8 hours ago
Michael Dunseith posted photos
8 hours ago
Dennis Heidner commented on Home Energy Magazine's blog post At Home with the Internet of Annoying Things
"Nice article. I am an electrical engineer, creating sensors for data collection and "possibly…"
9 hours ago
Chris Hunt commented on Home Energy Magazine's blog post At Home with the Internet of Annoying Things
"Hi Alan, You correctly identified a lot of the potential issues coming with the IOT or the…"
9 hours ago
Nicole Miller joined James Sayers's group
Thumbnail

Marketing Energy Efficiency

Sharing ideas, tools and examples of promoting energy efficiency to consumersSee More
11 hours ago
Avi Yashchin posted a video

CleanEdison: BPI Training

Avi Yashchin's former company, CleanEdison, provided education and training for those seeking clean jobs, These services included Exam Prep for Leadership in...
11 hours ago

© 2015   Created by Lawrence Berkeley National Laboratory.

Badges  |  Report an Issue  |  Terms of Service