At least, don't install it yet.
Having a central air-conditioning system designed and installed now is likely more expensive than necessary because your house isn't very airtight. A lot of the money you spend on the air-conditioning system and the money you spend running the AC is being blown right out the front door. And the back door. And the windows, the walls, and the roof. Additionally, a central air-conditioning system designed and installed now may be inadequate in 5-10 years as extreme summer weather worsens.
Though summer of 2022 in BC didn't bring any heat domes, we can expect the impending La Niño to bring more heatwaves this year and maybe a heat dome too. Maybe there will be another heat dome, maybe not. Regardless, it will be hot, and you will be uncomfortable in your home for some amount of time. Portable air conditioning units have only so much capacity, and they're probably already not keeping the rooms they're in sufficiently cool.
Imagine you've put away your groceries in the refrigerator, and you leave the fridge door wide open. A few hours later, the food isn't cold, and likely mostly spoiled. Solution? Buy a new, stronger refrigerator, of course.
Ridiculous, right? Of course, but that's what you'd be doing if you get an A/C system installed in your house right now. Why? Your house is leaky. I assume that your roof doesn't leak rain during a storm, but most houses have many gaps, cracks, and holes that add up to a large area through which air will enter or escape. You can read more about these leaks in my article "Better Indoor Air Quality Using Better Air Barriers", but the result in the summer is indoor air that has been cooled will leak out in some parts of your home and the stove range hood, bathroom fans, and laundry will send some of that cooled air straight to the exterior.
The best domestic air conditioning equipment generally available is only just able to deal with typical construction at current temperatures. A/C systems don't exactly cool air down to a specific temperature; an air conditioning unit of a given size can remove a certain amount of heat from the air. That roughly translates to reducing the temperature by a certain number of degrees, for a given size of room. For example, an air conditioner might can take air at 30°C and cool it down by 5°C to 25°C. If the heat from outdoors is causing the room to get up to 34°C, the air conditioner will bring the air down still only 5°C, and the room is at 29°C. You may feel as thought the aircon isn't working, but it's doing its job as it was designed.
Higher temperatures will require larger equipment -- bigger, more expensive aircon systems. For example, check on Google Maps satellite view for Google Earth, and look up the Palm Jumeirah. You'll see the houses there have very large cooling equipment on the roof - sometimes concealed under a roof - sometimes not. That is very expensive equipment. On the other hand, making your house far more airtight is nowhere near as expensive, and you can buy smaller AC equipment than your neighbour, and you'll be comfortably cool.
In my article "What Is The Cheapest Way To Heat And Cool Your Home?", I dig further into the AC options out there and provide a handy reference so that you can compare all the options at a glance.
Are you looking at renovating your home or building a new house in the Lower Mainland or Sunshine Coast of British Columbia and need some guidance? My free Project Roadmap lays out the process of a successful house construction project; you can download it below.
My free Project Planning Pack helps organize your research, estimate construction costs, and plan the rest of your project.