Dicho,
does the 1700 sq ft include the garage apt. ?
what part of the US are you in?
a 4 Ton seems to large for 1700 sq ft if you are also having new insulation put in.......... you should be pushing closer to 2,000 sq ft before thinking 4 Ton
just a quick figuring a 3 or 3.5 ton (MAX ) would be better for your 1700 sq ft.............. if the unit is to large it will short cycle, which will not remove the humidity in the summertime and will just run up the utility bill both summer and winter.....
a 35 yr old 3.5 ton would be lucky if it could provide 60 to 70 % eff. but todays standards, the equipment will perform efficiently very well, provided the contractor does a proper installation and sizes the duct work correctly......
most contractors undersize their ductwork installations to cut fdown on cost, which in return chokes the new equipment down and causes premature component failure....
Icould talk about this stuff for days..........
shoot me a PM or email if you need any help or tips ........ get at least a minimum of 3 quotes....... 5 preferably...
edit: you also didn't post what SEER rating that 4 Ton had , or if it is a single stage or 2 stage compressor ( heat pump I am assuming )...... also are they using distribution type duct layout, or a full blown sheetmetal duct system?
or are they using Flex & Ductboard?
lot of variables to look at............ did they include any type of air purification, air filtration, air cleaner, germicidal units, UV lights, etc???
hope this helps
TC
edit: my old email e-card I did HVAC for over 25 years....
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