For most homes in San Leandro, the right air conditioner comes down to four things: how much heat the house really gains on a warm afternoon, whether the ducts can move enough air, what the electrical panel can supply, and whether a heat pump would serve you better than a cooling-only system. The brand on the outdoor unit matters less than getting those four right, and a free in-home estimate should cover each of them before you compare prices.
When a new system makes sense
Most people start looking at installation for one of five reasons:
- The old system is failing. A compressor or coil failure on an older unit is often where repair stops paying off.
- Repairs keep coming back. Several service calls in a couple of seasons usually mean the system is near the end.
- Bills are high. Older, lower-efficiency equipment uses more electricity for the same cooling.
- Cooling is uneven. Some rooms are comfortable, others never cool down.
- The system is too small. Often after an addition or a garage conversion.
The last two are not always solved by new equipment. Uneven cooling is often a duct problem, and a room added later may be better served by a ductless mini-split. If your current system has one failed part and otherwise works, read the repair-or-replace guide first.
Sizing comes before equipment
Capacity should come from a load calculation (often called a Manual J) that accounts for floor area, insulation, window size and direction, air leakage and attic heat, not from the size of the old unit. An oversized air conditioner reaches the setting fast, shuts off before every room has cooled, and cycles more often. An undersized one runs all afternoon and still falls behind on the warmest days.
The ducts have to match the new capacity. A new outdoor unit will not fix a bedroom fed by a crushed attic duct or a house with one small return grille. We check supply and return airflow and the condition of the attic and crawlspace runs, and when they need work the estimate says so. Duct repair can do more for comfort than a premium compressor.
What a complete estimate spells out
| Item | What to look for |
|---|---|
| Capacity and efficiency | Size based on the load calculation; SEER2 and EER2 ratings |
| Indoor coil | Replaced with the outdoor unit as a matched pair |
| Refrigerant lines | Reused only if correctly sized and they pass a pressure test |
| Condensate drain | Where the water goes, plus a float switch for attic units |
| Pad or wall bracket | Placement, service clearance, noise toward bedrooms and neighbors |
| Electrical | Dedicated circuit, outdoor disconnect, panel capacity |
| Thermostat | Compatible with the new system’s stages or variable speed |
| Ductwork | Any repairs, sealing or return upgrades |
| Old equipment | Removal, with the refrigerant recovered rather than vented |
| Permit | Replacing or adding equipment normally needs a permit and inspection |
New residential systems now use newer refrigerants that older indoor coils were not designed for, which is one more reason the coil and the outdoor unit should be replaced together.
SEER2 and EER2 in plain words
Both ratings measure how much cooling you get for each unit of electricity; a higher number means a lower bill for the same comfort. SEER2 reflects a whole cooling season, EER2 a hot afternoon. Two-stage and variable-speed systems run longer at lower output, which keeps rooms steadier and runs quieter, at a higher purchase price. Where the AC works hard only for a limited number of weeks a year, the top efficiency tier pays back slowly, so we show you the trade-off instead of defaulting to either end.
What affects the price
Most installations fall between $3,500 and $12,000, including equipment and labor. The low end is a like-for-like replacement in an easy location with reusable lines. The price rises with higher-efficiency or variable-speed equipment, a heat pump instead of a cooling-only unit, adding air conditioning to a home that never had it, duct corrections, electrical upgrades and hard access such as a tight side yard, a low attic or a long line-set route.
You see the full price before any work begins. Financing is available, seniors and military households get 10% off, and we will beat any written quote. For a wider look at the numbers, see the HVAC installation cost guide.
Adding air conditioning to a furnace-only home
Many older homes here were built with a gas furnace and no cooling. If the furnace and ducts are in reasonable shape, central air is added by setting a coil on the furnace, running refrigerant lines and a drain, and placing the outdoor unit on its own circuit. The furnace blower has to move enough air for cooling, which we check before quoting. If the furnace is old too, price a heat pump alongside: one outdoor unit can replace both.
Local notes
Late-summer and early-fall afternoons are when San Leandro, San Lorenzo and Castro Valley get their real heat, and that is when a system sized by guesswork falls behind. Hillside homes such as those in Bay-O-Vista often have west-facing rooms that gain far more heat than the rest of the house; the load calculation should account for them, and thermostat placement matters too. In post-war homes with ducts in the attic, duct condition often decides how well a new system cools as much as the equipment does.