A system here has to survive the wind season and the power going off

Often not, and it is worth fifteen minutes before you call anybody. Compressors hold themselves off for several minutes after power returns, furnaces run through an ignition sequence, and connected thermostats may be waiting to re-join a network. After that, check three things: the breakers, the outdoor disconnect beside the condensing unit — a small grey box, and the one people forget — and that the switch beside the furnace or air handler is still on. If all three are fine and it still will not run, it is a real fault and worth a visit. Tell us what you found when you call.

Usually not, and there are two safety points that matter more than the answer. A portable generator produces carbon monoxide in lethal quantities indoors, and a garage with the door open counts as indoors — run it well clear of the building and fit a working carbon monoxide alarm before you ever start one. And powering a house by plugging a generator into an outlet is illegal and can kill a lineworker restoring power in your street; the only correct connection is a transfer switch or interlock fitted by a licensed electrician, which is not our trade and not something we will do. On the technical question: a compressor draws several times its running current when it starts, and most portables cannot supply that surge. A furnace blower or a ductless head is often within reach. The starting figure is on your equipment nameplate and we will read it with you.

Because of the grade. The inland side of the valley can run a long way above the coastal side on the same afternoon, so the design temperature a system is sized against genuinely differs between houses a couple of miles apart. That is why we do a room-by-room load calculation — glass and orientation, insulation, air leakage, shading, occupancy and what the ductwork can carry — rather than matching the tonnage that is already installed. Whoever chose that tonnage may not have calculated anything either.

The one your system can actually carry, which is a measurement rather than a matter of opinion. A higher-rated filter restricts more air; fitting one the equipment was not designed for reduces airflow, hurts performance and can damage the machine. We measure static pressure with the proposed filter in place and tell you what yours will take. Worth knowing as well: in most houses far more outside air arrives through gaps, the attic hatch and duct leakage than through any filter, so air sealing often does more than a filter upgrade. We will not make health claims about any of it, and you should be careful of anybody who does.

Mechanically, yes. An exposed unit collects leaves, seed and grit against its coil far faster than a sheltered one, and a blocked coil raises pressures, raises running cost and shortens the machine’s life. That is visible with a torch and it means a shorter coil-cleaning interval. Screening helps with debris and hurts airflow, so any screen has to respect the clearance the manufacturer requires rather than the look of it. What we will not do is quote you a number of extra years from a coating, a cover or a brand — that depends on your exposure and nobody can put a figure on it from the road.

Thousand Oaks, Newbury Park, Westlake Village, Agoura Hills, Oak Park, Camarillo, Moorpark and Simi Valley.