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Re: [Shop-talk] Furnace Filters

To: shop-talk <shop-talk@autox.team.net> definitions=2021-12-13_12:2021-12-13, 2021-12-13 signatures=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-2009150000 definitions=main-2112140067
Subject: Re: [Shop-talk] Furnace Filters
From: Tom Coradeschi <tjcora@icloud.com>
Date: Tue, 14 Dec 2021 06:36:54 -0500
Delivered-to: mharc@autox.team.net
Delivered-to: shop-talk@autox.team.net
References: <7A31A1A5-4974-420F-8A92-2DC3A90E5661@gmail.com>
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Now you=E2=80=99re getting to the point. Filtration efficiency is going to b=
e measured in MERV (and/or MPR, if you=E2=80=99re 3M) and should be independ=
ent of filter thickness.=20

What the 4=E2=80=9D filter buys you is (for the same filtration efficiency) l=
onger filter life, and, maybe, lower pressure drop across the filter. The $6=
4k question is: how much lower, and does it really make a difference? If you=
 do end up buying a differential pressure gage, would you be interested in r=
unning 1=E2=80=9D vs 4=E2=80=9D and reporting out what you see? You=E2=80=99=
d have to conjure up a way to seal up the duct so you get a good upstream re=
ading with the 1=E2=80=9D, I think.=20

Another ME here, albeit one who is not crazy about doing sheet metal work =E2=
=80=A6 at least not crazy enough that I see the point in going to a 4=E2=80=9D=
 filter, sans data showing it to be worth the effort. And I have a box full o=
f 1=E2=80=9D MERV 13 filters to use up - on a 3 month change cycle I am good=
 until early 2023, at this point:-)

Whatever you do, don=E2=80=99t stack 1=E2=80=9D filters. They will act like t=
wo resistors in series - your blower motor will almost certainly not respond=
 well to that.=20

Regards,

Tom Coradeschi
Tjcora@icloud.com

> On Dec 13, 2021, at 7:03 PM, Jim Stone <1789alpine@gmail.com> wrote:
>=20
> =EF=BB=BFThanks, guys.  That is all good feedback. David: I hadn=E2=80=99t=
 considered using a washable filter, but it is an interesting idea.  It look=
s like a 4=E2=80=9D one will cost me around $100, so the breakeven point is a=
fter a year.  Not too bad.
>=20
> But, here is an interesting point that showed up tangentially when I Googl=
ed =E2=80=9Cwashable furnace filters=E2=80=9D:=20
>=20
> Fortunately, most 20x25x4 air filters last between six to eight months. By=
 that calculation, the average homeowners will not need more than two 20x25x=
4 air filters in any given year. In contrast, a one-inch air filter will nee=
d to be changed every two to three months.  https://servicechampions.com/ben=
efits-of-a-20x25x4-air-filter-installed-in-your-furnace/
>=20
> If that is true, the cost difference between the 4=E2=80=9D and 1=E2=80=9D=
 disappears.  Thoughts?
>=20
> Jim=20
>=20
>=20
>> On Dec 13, 2021, at 5:32 PM, Pat Horne <patintexas@icloud.com> wrote:
>>=20
>> My shop air handler is set up to use a 2=E2=80=9D filter but the installe=
r said to use 2 one inch filters, both good ones. I watch the first one & re=
move it when it is too dirty, move the second one up & install a new second o=
ne.=20
>> There is some discoloration on the second filter, so it is doing somethin=
g.=20
>>=20
>> If you want to go with two different ones, I=E2=80=99d put the poorer one=
 first, followed by the better one.=20
>>=20
>> My HVAC guy says to not use the corrugated filters, nor the fiberglass on=
es that you can see throughout. He sells me Purolator 312 filters by the cas=
e.=20
>>=20
>> Peace,
>> Pat
>>=20
>> Pat Horne=20
>> We support Habitat for Humanity
>>=20
>>=20
>> On Dec 13, 2021, at 4:21 PM, Jim Stone <1789alpine@gmail.com> wrote:
>>=20
>> =EF=BB=BFThe company that installed my HVAC system a few years ago used a=
 filter box on the return line that takes 20=E2=80=9D x 25" x 4=E2=80=9D fil=
ters, which is an unusual, and thus expensive, size - filters generally run a=
bout $25 each - that is not readily available other than online.  During con=
struction, my general contractor just had a cheap 20=E2=80=9D x 25" x 1=E2=80=
=9D filter in there that seemed to work just fine.  I checked the installati=
on instructions for the furnace and there are no specifications for the filt=
ers, other than that they need to be changed regularly, which is getting pre=
tty expensive.  Is there any reason I couldn=E2=80=99t just use 1=E2=80=9D f=
ilters, which are less than half the price?  Maybe even put two of them in t=
he box, a good one first to catch most of the dust and a cheap one like the c=
ontractor used as a secondary one.  It is a snug fit and I don=E2=80=99t thi=
nk there is any danger of them tipping, but two would make it impossible.
>>=20
>> Thanks,
>> Jim
>> _______________________________________________
>>=20
>> Shop-talk@autox.team.net
>> Donate: http://www.team.net/donate.html
>> Suggested annual donation  $12.96
>> Archive: http://www.team.net/pipermail/shop-talk http://autox.team.net/ar=
chive
>>=20
>> Unsubscribe/Manage: http://autox.team.net/mailman/options/shop-talk/patin=
texas@icloud.com
>>=20
>=20
> _______________________________________________
>=20
> Shop-talk@autox.team.net
> Donate: http://www.team.net/donate.html
> Suggested annual donation  $12.96
> Archive: http://www.team.net/pipermail/shop-talk http://autox.team.net/arc=
hive
>=20
> Unsubscribe/Manage: http://autox.team.net/mailman/options/shop-talk/tjcora=
@icloud.com
>=20

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<html><head><meta http-equiv=3D"content-type" content=3D"text/html; charset=3D=
utf-8"></head><body dir=3D"auto">Now you=E2=80=99re getting to the point. Fi=
ltration efficiency is going to be measured in MERV (and/or MPR, if you=E2=80=
=99re 3M) and should be independent of filter thickness.&nbsp;<div><br></div=
><div>What the 4=E2=80=9D filter buys you is (for the same filtration effici=
ency) longer filter life, and, maybe, lower pressure drop across the filter.=
 The $64k question is: how much lower, and does it really make a difference?=
 If you do end up buying a differential pressure gage, would you be interest=
ed in running 1=E2=80=9D vs 4=E2=80=9D and reporting out what you see? You=E2=
=80=99d have to conjure up a way to seal up the duct so you get a good upstr=
eam reading with the 1=E2=80=9D, I think.&nbsp;</div><div><br></div><div>Ano=
ther ME here, albeit one who is not crazy about doing sheet metal work =E2=80=
=A6 at least not crazy enough that I see the point in going to a 4=E2=80=9D f=
ilter, sans data showing it to be worth the effort. And I have a box full of=
 1=E2=80=9D MERV 13 filters to use up - on a 3 month change cycle I am good u=
ntil early 2023, at this point:-)</div><div><br></div><div>Whatever you do, d=
on=E2=80=99t stack 1=E2=80=9D filters. They will act like two resistors in s=
eries - your blower motor will almost certainly not respond well to that.&nb=
sp;</div><div><br></div><div>Regards,</div><div><br><div dir=3D"ltr">Tom Cor=
adeschi<div>Tjcora@icloud.com</div></div><div dir=3D"ltr"><br><blockquote ty=
pe=3D"cite">On Dec 13, 2021, at 7:03 PM, Jim Stone &lt;1789alpine@gmail.com&=
gt; wrote:<br><br></blockquote></div><blockquote type=3D"cite"><div dir=3D"l=
tr">=EF=BB=BF<meta http-equiv=3D"Content-Type" content=3D"text/html; charset=
=3Dutf-8">Thanks, guys. &nbsp;That is all good feedback. David: I hadn=E2=80=
=99t considered using a washable filter, but it is an interesting idea. &nbs=
p;It looks like a 4=E2=80=9D one will cost me around $100, so the breakeven p=
oint is after a year. &nbsp;Not too bad.<div class=3D""><br class=3D""></div=
><div class=3D"">But, here is an interesting point that showed up tangential=
ly when I Googled =E2=80=9Cwashable furnace filters=E2=80=9D:&nbsp;</div><di=
v class=3D""><br class=3D""></div><blockquote style=3D"margin: 0 0 0 40px; b=
order: none; padding: 0px;" class=3D""><div class=3D""><font color=3D"#0433f=
f" class=3D""><span style=3D"caret-color: rgb(32, 33, 36); font-family: &quo=
t;Google Sans Text&quot;, arial, sans-serif; background-color: rgb(255, 255,=
 255);" class=3D"">Fortunately, most 20x25x4 air filters last between&nbsp;<=
/span><b style=3D"caret-color: rgb(32, 33, 36); font-family: &quot;Google Sa=
ns Text&quot;, arial, sans-serif;" class=3D"">six to eight months</b><span s=
tyle=3D"caret-color: rgb(32, 33, 36); font-family: &quot;Google Sans Text&qu=
ot;, arial, sans-serif; background-color: rgb(255, 255, 255);" class=3D"">. B=
y that calculation, the average homeowners will not need more than two 20x25=
x4 air filters in any given year. In contrast, a one-inch air filter will ne=
ed to be changed every two to three months. &nbsp;</span></font><a href=3D"h=
ttps://servicechampions.com/benefits-of-a-20x25x4-air-filter-installed-in-yo=
ur-furnace/" class=3D"">https://servicechampions.com/benefits-of-a-20x25x4-a=
ir-filter-installed-in-your-furnace/</a></div></blockquote><div class=3D""><=
div><br class=3D""></div><div>If that is true, the cost difference between t=
he 4=E2=80=9D and 1=E2=80=9D disappears. &nbsp;Thoughts?</div><div><br class=
=3D""></div><div>Jim&nbsp;</div><div><br class=3D""></div><div><br class=3D"=
"><blockquote type=3D"cite" class=3D""><div class=3D"">On Dec 13, 2021, at 5=
:32 PM, Pat Horne &lt;<a href=3D"mailto:patintexas@icloud.com"; class=3D"">pa=
tintexas@icloud.com</a>&gt; wrote:</div><br class=3D"Apple-interchange-newli=
ne"><div class=3D""><meta http-equiv=3D"content-type" content=3D"text/html; c=
harset=3Dutf-8" class=3D""><div dir=3D"auto" class=3D"">My shop air handler i=
s set up to use a 2=E2=80=9D filter but the installer said to use 2 one inch=
 filters, both good ones. I watch the first one &amp; remove it when it is t=
oo dirty, move the second one up &amp; install a new second one.&nbsp;<div c=
lass=3D"">There is some discoloration on the second filter, so it is doing s=
omething.&nbsp;</div><div class=3D""><br class=3D""></div><div class=3D"">If=
 you want to go with two different ones, I=E2=80=99d put the poorer one firs=
t, followed by the better one.&nbsp;</div><div class=3D""><br class=3D""></d=
iv><div class=3D"">My HVAC guy says to not use the corrugated filters, nor t=
he fiberglass ones that you can see throughout. He sells me Purolator 312 fi=
lters by the case.&nbsp;<br class=3D""><br class=3D"">Peace,</div><div class=
=3D"">Pat</div><div class=3D""><br class=3D""><div dir=3D"ltr" class=3D"">Pa=
t Horne&nbsp;<div class=3D"">We support Habitat for Humanity</div><div class=
=3D""><br class=3D""></div></div><div dir=3D"ltr" class=3D""><br class=3D"">=
On Dec 13, 2021, at 4:21 PM, Jim Stone &lt;<a href=3D"mailto:1789alpine@gmai=
l.com" class=3D"">1789alpine@gmail.com</a>&gt; wrote:<br class=3D""><br clas=
s=3D""></div><div dir=3D"ltr" class=3D"">=EF=BB=BF<meta http-equiv=3D"Conten=
t-Type" content=3D"text/html; charset=3Dutf-8" class=3D"">The company that i=
nstalled my HVAC system a few years ago used a filter box on the return line=
 that takes 20=E2=80=9D x 25" x<b class=3D""> 4=E2=80=9D</b> filters, which i=
s an unusual, and thus expensive, size - filters generally run about $25 eac=
h - that is not readily available other than online. &nbsp;During constructi=
on, my general contractor just had a&nbsp;cheap 20=E2=80=9D x 25" x <b class=
=3D"">1=E2=80=9D </b>filter in there that seemed to work just fine. &nbsp;I c=
hecked the installation instructions for the furnace and there are no specif=
ications for the filters, other than that they need to be changed regularly,=
 which is getting pretty expensive. &nbsp;Is there any reason I couldn=E2=80=
=99t just use 1=E2=80=9D filters, which are less than half the price? &nbsp;=
Maybe even put two of them in the box, a good one first to catch most of the=
 dust and a cheap one like the contractor used as a secondary one. &nbsp;It i=
s a snug fit and I don=E2=80=99t think there is any danger of them tipping, b=
ut two would make it impossible.<div class=3D""><br class=3D""></div><div cl=
ass=3D"">Thanks,</div><div class=3D"">Jim</div><span class=3D"">____________=
___________________________________</span><br class=3D""><span class=3D""></=
span><br class=3D""><span class=3D""><a href=3D"mailto:Shop-talk@autox.team.=
net" class=3D"">Shop-talk@autox.team.net</a></span><br class=3D""><span clas=
s=3D"">Donate: <a href=3D"http://www.team.net/donate.html"; class=3D"">http:/=
/www.team.net/donate.html</a></span><br class=3D""><span class=3D"">Suggeste=
d annual donation &nbsp;$12.96</span><br class=3D""><span class=3D"">Archive=
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lass=3D"">http://autox.team.net/archive</a></span><br class=3D""><span class=
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/a></span><br class=3D""><span class=3D""></span><br class=3D""></div></div>=
</div></div></blockquote></div><br class=3D""></div><span>__________________=
_____________________________</span><br><span></span><br><span>Shop-talk@aut=
ox.team.net</span><br><span>Donate: http://www.team.net/donate.html</span><b=
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