What the software has to do
An air conditioning job has a shape that most trades do not. Between the doorbell and the deposit an installer has to measure a room, work out a heat load, choose a unit that covers it, draw where it goes and how the pipe runs, price the whole thing off their own rates, put it in front of the customer, get it signed, take the money, order the kit, fit it, record the refrigerant, and hand over a pack. Then service it every year.
General tools are good at the parts of that which every trade shares — the calendar, the customer list, the invoice. They know nothing about the parts that make it air conditioning: the load, the unit, the condenser, the F-Gas record. So the choice is really about how many tools you are willing to run, and how much retyping between them you can stand.
The four options
A spreadsheet and Word
Where most firms start and where a great many good ones still are. Free, flexible and entirely yours. The cost is the evening: every quote is typed by hand from notes taken on site, every price is looked up, nothing checks the arithmetic, and the survey, the quote and the F-Gas log live in three places that do not know about each other. The longer comparison with spreadsheets goes through it honestly, including what the spreadsheet does better.
A general field-service app
Built for any trade: jobs, scheduling, a customer record, a mobile app for the engineer, invoicing. Strong on the diary and on getting an engineer to the right address. Weak on the parts that are specifically air conditioning — it does not size a room, does not know what a condenser is, and its quote is a list of lines you type. Many installers run one of these alongside a spreadsheet for the sizing.
A general quoting tool
Built for producing a good-looking proposal and getting it signed. Usually does that well, with templates, e-signature and sometimes a payment link. The proposal is only as good as what you type into it, though: the load, the unit choice and the price all come from somewhere else, and the F-Gas side and the install pack are not its concern.
FoxFace
Built for one trade and one shape of job. The survey feeds the design, the design feeds the quote and the install pack, and the same record carries the F-Gas log and the handover pack. It does the air-conditioning parts the general tools cannot, and it does the general parts — the board, the customer record, the invoice — well enough that most firms run it on its own. The cost is that it is for air conditioning installers and nobody else.