Wate Heaters Tank or Tankless[2]

8/9/2019 Wate Heaters Tank or Tankless[2]

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WaterHeaters:

Tank orTankless?

By dave yaTes

m e the i ht choice, d eve etstuc i cold showe i

Acco d g o h U.S. D p m o e gy, h s co s

o hom s u gy us . w h h poo ubs, mu pd du d sh sh s o h s ck o b com g s d d

hom s, hos p c g s k y o h co s v v smos -mod s hom s, h g s co s ss u o you

Choos g h b s h o you hom h s b com mo chy s s d s g s h v s p h dus y d s g gy cos s h

s y b o s. i sp o h p om s o h h gh- ch h so ks d o h od y s d h ms v s c go k ss?

U o u y o co sum s, h cho c s o sy o m k . Cos s d y, d h s - xp s v h m gh b h o h

o you s v gs ccou ov m . H som s s o commo qud c s b k d k ss h s, c ud g

ch yp o ks d ho o s z o ccu y o m you ds.

Dave Yates owns and operates F.W. Behler Inc., a mechanical-contracting firm i York, Pa. Technical drawings by John Hartman; illustrations by Jackie Rogers.

Why shouldnt I buy the least-expensive water heater available? ev y b , bu pu ch s p c s o y po o o h mo y youv s h . l -cyc cos s c ud s o , op o , m c , d

v u y p c m o you h .Mos mpo , you go g o sp d mo mo y o h u co sum d by you

h h o y h g s . fu yp d c cy shou d b gh d c u y. Commo u so h s c ud c c y, g s, d o . fu cos s d v b y v y, so s goodd o ch ck p c s you b o m k g pu ch s . w h h s cos s m d, you c

choos h mos cos - c v mod .

AQ

COPYRIGHT 2007 by The Taunton Press, Inc. Copying and distribution of this article is not permitted.


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. hom bu d g.com fall/winter 2007

Tank: Low up-front costs,straightforward to instaLL

The bu e (ohe ti ele e t ielect ic odels) i

t -style w tehe te is co t olledby the ost t.Whe the w testo ed i the tf lls below sette pe tu e, thebu e fi es. Whe

hot-w te v lveis ope ed t fixtu e, w te isd w f o thetop of the t dis epl ced t thebotto of the twith cold i co iw te th ou h thedip tube. I sul tio

i i i es st dbyhe t loss, d

ode odp eve ts co osioof the t .

The mosT common Type o f waTer heaTer i ho es tod y,t -style odels eep hot w te e dy fo use i 30- to 120- l.sto e t s. Fuels i clude elect icity, s, d oil, but t -stylew te he te s lso c be p i ed with sol powe , he t-pu pdesupe he te s, d othe hyb id e e ts.

P ope ly si ed, t -style w te he te c supply ple ty of hotw te eve fo l e f ily. If the t is too s ll, hot w te is

depleted quic ly. If the t is too l e, e e y is w sted i t i -i the te pe tu e of u eeded hot w te . I f ct, st dby he tloss is the e test d wb c of t -style he te s. If hot w te isused o ly fo t i couple of showe s i the o i d fow shi dishes t i ht, lot of e e y is w sted eepi w te hotwhile you e t wo o sleepi . Fo this e so , t -style w tehe te s ust be well i sul ted. Fo tu tely, d to y i sul tio

equi e e ts h ve educed st dby he t loss co side bly. You ci c e se t s pe fo ce by ddi exte l i sul ti j c et.

pros cons

Will switching to a tankless water heater really save 50% on my utility

bills as some manufacturers advertising suggests?

Y m v ,bu k y 50%. l s s y you x s g s y h d h mod you co s d g bo

82% op g c cp. 71). wh h bu s h g , h s o d

u co sump o . th s v gso p y h h bu -

s o op g. Youk-s y h h s

o d b cks. U ss s c c, v s

o h ch m y,h h s co -

s d d gs d h up hu . a hough

h k ssu d,

h s sm buco s mou o h osssu ou d g . th s c o

o h ov cc o , ou d 19%, h ch s

ho much you c s v by s co k ss h .

how i t works

Dip tube

The ost tco t ol

Bu e

I sul tio

a odeod

Flue b ffle

Ve t pipe

Ove flowd i

D i

v lve

AQ

Lowest up-f o t costs E siest i st ll tio d

epl ce e t So e odels do t

equi e elect icity toope te

Uses wide v ietyof v il ble fuels

C be loc tedywhe e i ho e

Wo s well witheci cul ti syste s

St dby he t loss C u out of

hot w te

T s e l e he vy Hi he life-cycle co Te pe tu e co t

i ht ot be p ecis

Co bustio i

I co icold w te

Hot w teto fixtu e



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TanKless o r on -demand waTer heaTer s do t eep supply of hot w te o h d; theyhe t w te o ly s eeded. T less odels used

s ho es p i y hot-w te sou ce typic lly

e fueled by s, butso e elect ic odels e

v il ble. althou h theyi i i e st dby he t loss

d co su e less e e yth t -style odels,t less w te he te s h ved wb c s of thei ow .

O the o e h d, theyequi e specific de d

fo hot w te befo e theytu o ( t le st1 2 l.pe i ute), which esthe t ic y to use with

low-volu e eci cul tisyste s. O the othe h d,too uch de d fo hotw te t o e ti e (two o

o e people showe it o ce, fo ex ple) c

test t less he te sc p city. The te pe tu eof i co i w te c ffectthe he te s pe fo ce

d ust be co side edwhe choosi the i htsi e. also, e dless hot

w te c be bused,di i ishi o eli i tie e y s vi s. Fi lly,

et ofitti t less w tehe te c be expe sivep opositio .

tAnKLeSS: continuous hot water with Long-terM saVings

pros Lowe life-cyc

costs E dless hot w ru s o ly whe

eeded, offe ithe pote ti l tos ve e e y

accu te te petu e co t ol

S ll d sp cs vi ; typicw ll-hu

cons

T less w tehe te s ( lsoc lled fl sh oi st t w tehe te s) tucold w te hot

l ost s quic lys it c flow

th ou h theu it. Whe hot-w te v lveis ope ed t

fixtu e dw te be i sto flow th ou hthe he te , theflow se sofi es the bu e(o he tiele e t ielect ic odels).W te li escoil ou d thehe t exch e ,he ti w teto the desi edte pe tu e.Whe the v lveis closed, theflow se so tu soff the bu e .

Our teenagers stay inthe shower until theres no hot water left for

my husband and me. What can we do?

Y ll lh d v u ou o ho

g . Bu d ss ho com s cos . O c h s o mo co cbou u g ou o ho

, you g s p ob-b y s y h shoo g . You, oo, m gh g .

th c s d us g m gh ob o c b u you u y b v s d h s v

o h o b ou d. i c , iv s b s c s o jus

ho w i t works

Whats a Btu anyway? a B t t t t

q t t t t t t

1 b. t b 1f. g - - t t

Bt - - t . f t tt , t t tt t b 3.4128

t t t q t Bt t .

Huh?

Hot w teto fixtu e

Exh ust

The ost t

He t exch e

Bu e

Flowse soI co i

cold w te

AQ

Hi he up-f ocosts

Co plic ted i

l tio ; l eli es ofte eq Elect icity eq

fo ost odelope te

U t e ted wle d to sc li

educe o h l C suffe f e

d e if i pe ly i st lled

mi i u hot-wflow equi ed

reci cul tio io e difficult,

pote ti l to cop o ise w

Pho os: Cou sy o h

Co t ol p el

F

I co i

fuel



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Our neighbors have both a tank and a tankless water heater in their house. Is that wasteful?

n ly.th so s o h v bo h. th h s md p s o h hous . iv b k o o s k ss m s su d sm k-s y h o h k ds b hs. thbus d ss ho . H v g o s o s u h h s h x u s h y s v . add g ho - c cu o oop o k

Bu dd g c cu o oop o k ss mod s mo comp cvo d o sho s y. th s s o h c s h bo h yp s m y b

Can I save some money by installing a water heater myself?

i y y, you c ck h s o o k-s y h , bu i h k k ss sb s o p os. fo s s, c b cky o d pp op p c o s k ss hs d -mou d, h ch ys qu s p g h hous d som m s m s d g o co c , bb ck s. a bu ch o c c co c s x s : exh us mus b k p s d s c om doo s d -do s, co d o s, ou s, g s m s, d s o , mo g o h h gs (s V g: - d-d hco s d o , c g p g ). i h s oc o s om you x s g h , you d o c -cu h s z o co d- d ho - s o m k su h s ough o o d h x u s. i

h s d up u d s z , p o m c su . t k ss h s qu g B u puh k-s y h s, so you k y d g u s, oo. add g o h s , d h s oo do gh . ev you co d d sp h s co c s, mos p o ss o s o o -y -

y o bo d m s, h ch i h k s o h h cos o s o .

O e 80- l. - ylw te he te o two50- l. t s with o e dedic ted to the stesuite e the best optio . t l w tehe te s loc ted close to poi ts of use i ht bethe best v lue (o e l e t less odel fo twob ths, d o e s lle u it fo the thi d b th).

Howeve , o e l e t less u it could lso besufficie t ( i i u 190,000-Btu i put, if flowtes e i withi bou d ies).

a l -v l m l (120 l. o l e )is ost li ely eeded to eet pe de d.Sep te s lle w te he te s ssi ed toi dividu l o s ll oups of b th oo s, o b l w te he te s, i htbe equi ed. This would be t e ted o e li e co e ci l pplic tio th eside ti l setti .

h m 4+ b :

mo , D d, d Ju io h ve 50- l.,s-fi ed t -style w te he te with

ope ti efficie cy of 82% d 50,000-Btu i put. Occ sio lly, they u out of hotw te d w t to ow why. I expl i edth t it equi es 666.4 Btu to ise 1 lloof w te f o 40F to 120F (the lowestco o te pe tu e fo i co i w te tothe ve e te pe tu e setti fo w tehe te ). But befo e I et to the th, letsloo t the f ilys hot-w te us e h bits.

Eve y o i , mo showe s fo ei hti utes; D d follows fo 12 i utes; d

Ju io be i s 15- i ute showe wheD d is idw y th ou h his. D d the sh veswith the f ucet u i hot w te fo th ee

i utes du i Ju io s showe . Lets ssu eth t showe i co su es 2 1 2 l. pe i ute( p ), t 110F, fo tot l of 35 i utes.Th ts 70F te pe tu e ise, o 1475.75Btu pe i ute (88,545 Btu pe hou ). Divideby 666.4, d we dete i e th t 2.19 pwill eed to co e f o the w te he te foe ch showe . add 4 1 2 l. fo sh vi , dthe f ily eeds little ove 81 l. of hotw te i 38 i utes.

Why do they occ sio lly u out of hotw te ? Thei t h s 50 l. of hot w te ost dby, but s soo s they st t usi hotw te , they lose 5 l. s i co i cold w te

Below, youll find some guidelines t t t- z t t t t . B t , t t , t t t t z t k t k t t

b t t t . s x t t t

SiZe MAtteRS: ge t i t r igh t, do the Math

3-b m 3 5 l :

ixes i to the t . Whe ope ti , theiw te he te c p oduce 1.25 l. pe 50,000 Btu i put x 0.82 ope ti efficie41,000 et e e y i put 666.4 = 61.5 po 1.25 p . So they st t with 45 l sto

d the he te p oduces 47 1 2 l. du i38- i ute showe i ti e. Th ts tot l o921 2 l. v il ble fo thei o i oIf yo e st ys i the showe fo few e

i utes o tu s o the dishw she , theiw te tu s cold. To eep f o u i ohot w te with othe t -style w te it eeds to h ve l e t c p city,

ecove y te, o both.To si e t less w te he te fo the

we st t with the pe pe - i ute hot-w tde d. I the c se of mo , D d, d Jutwo ove l ppi showe s co su e 4.38 pof hot w te : 4.38 x 666.4 Btu pe llo 2918.83 Btu pe i ute o 175,130 Btu pehou . Th ts et Btu. We divide by the opeefficie cy (0.82) to et 213,573 i i u i put to eet pe de d. D ds hot-w teuse while sh vi c be i o ed u less t

e othe co cu e t uses, such s dish wd/o clothes w shi .

1-b m 1 2 l :a 30- l. i ht wo , but 40- l. t -

style w te he te is less expe sive to pu ch se.a l u it should h ve 140,000-Btu i putif the e e y f cto is 0.82 o e te .

a 40- to 50- l. should be sufficie t,depe di o lifestyle. t l odels shouldh ve 190,000-Btu i put if the e e y f cto is0.82 o e te .

2-b m 2 3 l :

AQ

AQ

Le o e bout si i w te he te s,d see life-cycle costs o li e.

f h b .



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It sounds as if youre

leading us toward choosing a tankless watheater. Is a tank-style water heater ever a better choice?

i l l h y gy- c

mo y. Bu h y o b s cho c . fo s s, hch s d s o cos

m s u o d b , sp co v h hous oo z h s v gs. t

h s so h v us g p oh som o ks c g u

cu y h co d-bubb o co d c su

h you u g ho o o (usu y u d3 4

p m u h s gx mp ). f y, mos

h s qu op . You m gh p

c o h v g g o h d du g po

Venting: a Life-and-death considerationone advanTage of an elecTric waTer heaTer t t t t q t . Tb t t, t , t t t t t- x . i

k t b t t t , t t x tt t . B t t k t k t t b

t t . K t t bx k , t t j t tb . f t t t . i

q t b t t , t .

at tIf you house h s chi ey, ost t -style w te he te sc be ve ted t osphe ic lly, which si ply e s th t co -bustio ses o up the chi ey u ssisted. Co bustio iis d w f o i side the house, d exh ust is ve ted f othe w te he te th ou h lv i ed pipes i to the chi ey.

amErICan g t ; t ka. O. SmITH g t ; t k t kBOCk g ; t kBOSCH g t ; t k

BraDFOrD WHITE g , , t ; t k

t knOrITz g ; t kPaLOma

g ; t krHEEm g t ; t k t krInnaI g ; t kSEISCO e t ; t kTakagI g ; t kU.S. CraFTmaSTEr g t ; t k

s b t

a setup si il to di ect ve ti , se led co bustio is optio i situ tio s whe e the w te he te i ht bei st lled e fl ble o co osive p oducts. a se ledch be eli i tes the ch ce of y i side i beid w i to the w te he te i this syste .

AQ

manufacTurers

p t tPowe ve ti is do e th ou h sidew ll fo botht d t less w te he te s. Bec use the ho i-

o t l exh ust pipes do ot c e te tu l d ft,powe -ve ted w te he te s use s ll elect icblowe to exh ust co bustio by-p oducts fo cibly.Co bustio i is still d w f o i side the ho e.

B b t t tIf you live i ti ht house with co t olled ve til tio , you

i ht ot w t to d w co bustio i f o i side. Di ectve ti is optio . Pipes fo i co i co bustio i dout oi exh ust e i co po ted i to o e syste th t pe -et tes sidew ll o oof.

fall/winter 2007

A sealed combustion chamber allows no inside air to enter.

Exh ust out

Co bustioi i

Exh ustout

Co bustioi i

Co bustio i i

Co bustioi i

Exh ustout

Exh ust out

COPYRIGHT 2007 by The Taunton Press Inc Copying and distribution of this article is not permitted

Wate Heaters Tank or Tankless[2]

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