# Mini Split Guides for San Diego Homes > Mini split guides for San Diego homes: sizing, coast vs inland, placement, condensate, electrical, permits, rebates, running cost and installation cost. URL: https://mesaminisplitsandiego.com/guide/ Plenty of San Diego homes were built without ducts or air conditioning, and the questions start the first hot week: how many heads, where the outdoor unit can go, what the City permit involves, what it costs to buy and to run. These guides answer them for San Diego's mix of coastal and inland climates, from the cornerstone guide on adding AC to a home without ducts to the cost guide with published permit fees. Start with the question in front of you; each guide links to the next decision. ## Learn how it works - Learn [Do you need air conditioning in San Diego? A guide to adding AC to a home without ducts](https://mesaminisplitsandiego.com/guide/adding-ac-to-san-diego-home-without-ducts/)Why so many San Diego houses were built without air conditioning or ducts, how to tell whether yours needs it, and what adding cooling without ductwork involves, from sizing and placement to permits, HOAs, cost and upkeep. - Learn [Do you need a permit to install a mini split in California?](https://mesaminisplitsandiego.com/guide/mini-split-permits-san-diego/)What California's Energy Code requires for a new mini split, how the City of San Diego, the County and other local cities issue the permit, what the inspection and field verification cover, and what SB 222 changes from 2027. - Learn [How long does it take to install a mini split?](https://mesaminisplitsandiego.com/guide/mini-split-installation-process/)There is no honest single number. What sets the timeline is the scope: how many heads, how far the lines travel, whether the panel needs work and how the permit and inspections fall. Here is the sequence and what stretches each part of it. - Learn [How does a mini split condensate drain line work?](https://mesaminisplitsandiego.com/guide/mini-split-condensate-drainage/)Every indoor head makes water when it cools, and humid coastal San Diego makes plenty. Where that water goes, by gravity or by pump, decides whether a mini split stays dry for years or drips down a wall. - Learn [What are the electrical requirements for a mini split?](https://mesaminisplitsandiego.com/guide/mini-split-electrical-requirements/)How the circuit, breaker and wire for a mini split are chosen from the equipment's own nameplate, why the outdoor unit gets a disconnect beside it, and how to tell whether an older San Diego panel has room or needs a service upgrade. - Learn [Mini split noise levels: how loud is a mini split?](https://mesaminisplitsandiego.com/guide/mini-split-noise/)Inverter mini splits are among the quietest ways to cool a room, but a published decibel rating is a test-lab number. What you and your neighbor actually hear depends on distance, walls, mounting and the hours the unit runs. - Learn [Mini split operating cost in San Diego: what does it cost to run?](https://mesaminisplitsandiego.com/guide/mini-split-operating-cost-san-diego/)How to turn a room's cooling or heating load, the hours a head runs and its efficiency rating into kilowatt-hours, then into dollars on SDG&E's published time-of-use rates, and why heating against gas is a closer call than cooling. - Learn [What size mini split do I need?](https://mesaminisplitsandiego.com/guide/mini-split-sizing/)Mini split size is a load question, not a floor-area question. This guide explains BTUs and tons, what a Manual J calculation measures, why inverter turndown matters as much as maximum output, and how the same room can need different equipment at the coast and inland. ## Decide what to do - Decision Guide [Mini split outdoor unit placement: where should it go?](https://mesaminisplitsandiego.com/guide/mini-split-placement/)The outdoor unit's location sets the line-set route, the noise a neighbor hears, how long the coil lasts near the coast and which permit path applies. Here is how to choose it, and where the indoor head should go once it is chosen. - Decision Guide [Mini split vs central air: which is better for your home?](https://mesaminisplitsandiego.com/guide/mini-split-vs-central-air/)The deciding question is usually the ductwork: whether the house has ducts, and what shape they are in. This guide works through ducts, comfort, efficiency ratings and cost, and says plainly when a ducted system is the better choice. - Decision Guide [Mini split vs window unit: which should you choose for one room?](https://mesaminisplitsandiego.com/guide/mini-split-vs-window-unit/)A window unit is cheap, quick and needs no permit. A mini split costs more and needs one, but it is quieter, leaves the window alone, heats as well as cools and adjusts its output to the room. Which is right depends on how long you will be there and how the room is used. - Decision Guide [What should you look for in a mini split for coastal areas, and what changes inland?](https://mesaminisplitsandiego.com/guide/mini-split-coastal-vs-inland-san-diego/)Choosing a mini split for coastal areas is a different job from choosing one inland, because San Diego County puts two very different climates a short drive apart. Near the water the problems are salt and moisture; in the inland valleys they are heat, sun and cold nights. Here is how each one changes the equipment, the placement and the sizing. - Decision Guide [Single zone vs multi zone mini split: which layout is right for your home?](https://mesaminisplitsandiego.com/guide/single-zone-vs-multi-zone/)One outdoor unit per room, or one outdoor unit for several rooms? The answer turns on how the rooms are used, how their loads compare, how much yard there is for equipment and how much a single failure would matter. - Decision Guide [What types of mini split indoor units are there?](https://mesaminisplitsandiego.com/guide/mini-split-indoor-unit-types/)Wall-mounted heads, ceiling cassettes, floor consoles and concealed duct units all do the same job with the same outdoor unit. They differ in how they throw air, where their water goes, how a technician reaches them, how they look and what they add to the price. ## Plan the cost - Cost Guide [Is there an SDG&E rebate for a mini split?](https://mesaminisplitsandiego.com/guide/mini-split-rebates-san-diego/)The full San Diego incentive picture for ductless heat pumps: the federal credit that ended, the state and City programs that closed, the income-qualified programs still open, and the SDG&E rate any heat pump household can choose. - Cost Guide [How much does mini split installation cost in San Diego?](https://mesaminisplitsandiego.com/guide/mini-split-installation-cost-san-diego/)Typical San Diego-area ranges by number of indoor heads, the published permit fees, the parts of a price that only a site visit can settle, and an honest look at rebates and running costs.