Buying and installing a new AC in a Nellore home: tonnage to placement

Choosing an AC for a Nellore home comes down to four decisions: the tonnage for the room, inverter or fixed-speed, what the outdoor unit is made of, and where the two units go. Get those right and the installation — ₹899 on our rate card, bracket to trial run — is the easy part. Get the tonnage or the placement wrong and no amount of servicing fixes it.

This guide is written for the heat here: 40°C-plus from March to June, humidity most of the year, and salt air on the coastal side.

Tonnage: size for the room and the roof

Floor area is the starting point, not the end.

Room size	Starting tonnage
Up to about 120 sq ft	1 ton
120–180 sq ft	1.5 ton
180–250 sq ft	2 ton

Then adjust:

• Top floor under a concrete roof: add half a ton. The slab stores the day's heat and releases it all night.
• West- or south-facing room with big windows: add half a ton, or fit thick curtains and keep the size.
• Kitchen adjoining, or many people: add half a ton.
• Ground floor, shaded, small windows: you can stay at the base figure.

Undersizing is the common mistake here. A 1-ton unit in a 170 sq ft west-facing bedroom runs flat out all evening, never reaches 25°C, and wears out young.

Inverter or fixed-speed

An inverter AC changes compressor speed to hold the set temperature; a fixed-speed unit switches the compressor fully on and fully off. For a bedroom or hall that runs hours every day for eight months, the inverter's lower running cost pays back the price difference and the unit handles long runs more gently. For a guest room used occasionally, a fixed-speed unit is fine and cheaper to repair.

Star rating matters in the same way: the more hours the AC runs, the more a higher rating saves. A 5-star inverter in the bedroom you sleep in every summer night is money well spent; the same rating on a rarely used room is not.

What to insist on for a Nellore home

• Corrosion-resistant condenser coil if you are anywhere on the coastal side — Muthukur, Krishnapatnam, the eastern edge of the city. Brands sell coated coils under names like blue fin or gold fin. They resist the salt that otherwise eats fins and pinholes the copper within a few years.
• A copper coil rather than aluminium where the choice exists; copper is repairable when it leaks, aluminium usually is not.
• A wide operating voltage range in the specification, for the evening dips. Fit a stabiliser anyway for the spike when power returns.
• Dry mode and a self-clean or auto-dry function, both of which earn their keep in the monsoon.

Where the indoor unit goes

• High on a wall, about 7 to 8 feet, with the air blowing along the length of the room, not straight at the bed or a door.
• Not directly above the TV, a wardrobe or the bed head; drips happen, and you want the unit reachable for filter cleaning.
• On an outside wall or close to one, so the copper run is short. Every extra metre of pipe is a part, costs cooling, and is one more place for a leak.
• With a slight fall towards the drain, which the installer sets; a unit mounted dead level or tilted the wrong way drips inside within a month.

Where the outdoor unit goes

This decides more of the unit's life than people realise.

• Airflow first. At least a foot clear at the back and sides and a few feet in front of the fan. A unit in a box or a recess rebreathes its own hot air and runs hotter than the weather.
• Shade if possible. A north or east wall is better than a west one, which gets the full afternoon sun. If the terrace is the only option, a small open-sided shade above it helps.
• Away from the sea breeze where you have a choice, on the coastal side.
• On a proper bracket, fixed to a solid wall, with rubber pads. Not on a loose stand on a parapet, and not on a neighbour's wall without agreement.
• Reachable for service. If a technician needs a ladder and a harness to wash the coil, the coil will not get washed.
• Not above a bedroom window or a neighbour's; the fan and compressor are not silent.

Before the installer arrives

• A dedicated electrical point with its own MCB, wired for the current on the nameplate. If it is not there, that is an electrician's job before installation day, not during it.
• Decide where both units go and mark the wall; you know the room better than the installer does.
• If an old unit is coming down, book the uninstallation (₹499, with gas recovery) as well, and ask whether the existing copper line set is sound and the right size for the new gas before reusing it. Many R-32 installs go on fresh pipe.

What happens on the day

The indoor unit is mounted, the wall cored, the outdoor unit fixed on its bracket, pipes and drain run and insulated, the electrical connection made, the lines vacuumed, the valves opened, and the unit run and checked for cooling and drips. Anything beyond what comes in the box — extra pipe, a longer drain, a stand — is priced at MRP and shown to you before it is used. A trial run with the door shut and a temperature check at the grille is the last step; do not let the installer leave before it.