A simple question has such a complicated reply

How do I update the energy efficiency of my home

I have seen this question so many times, there is no simple answer, each house is individual, from orientation to build quality, But some methods might be worth exploring. The notes below will help, but it's such a wide area of research,

Let's split the information into two separate camps Winter and Summer

Winter

It is here we find most home improvements being applied, some a complete disaster, some a complete waste of money, but some do add to the house comfort levels.

Loft

Here is the easiest way to improve the house level of comfort, add as much insulation as possible 200mm, will give an immediate comfort improvement, but there is a caveat or two, there will be a lot of electric cables feeding lighting and possibly plugs, together with tv cables and aerials, these need protection to prevent overheating. Next, the improvement will need adequate ventilation to remove the condensation risk. Finally don't forget to update and insulate the loft access panel, and whilst you’re at it, improve the access with a folding ladder. Plus too much insulation is a waste, do the calcs to work out the optimum.

Doors

If at all possible look at upgrading the external doors together with seals, is it possible to add a small canopy to your doors to shade and keep the rain away, or a porch to add that valuable lobby.

Windows

Windows are next but is in the next level as far as cost is concerned. but will add massively to the overall improvement of energy loss. there are many alternatives, choose wisely, but triple glazing is a must. Whilst I am here as a larger investment, a conservatory adds a large upgrade avenue for thermal and cooling, plus adding extra room to the smaller house, there are many excellent designs with some very high insulation qualities.

Walls

Some might think wall insulation should be included, if your house is a recent build and has a cavity then yes, but be careful, insist on a full cavity survey, with video probes, looking for a clear cavity, Choose the fill carefully and only go with a full guarantee and an approved British standard system and if possible with an agreement certificate.

Walls with no cavity is in a different league, consider first the mortar joint, does it need raking and repointing, it might not improve directly your heating bill, but its the first-line defence on water leaking in so worth doing. Next look at the house as a whole, do the gutters leak and are the downpipes, water running down a wall is not a good idea. Can you insulate, the answer id yes, but this needs careful investigation, externally, insulation will solve many of the walls problems, a good thin but high-efficiency sheet insulation with a thin render will look good but do not fall foul of the planners, check to see if they need an application made. Internal insulation is also possible and will avoid the planning problems, but it opens up some technical condensation problems, a simple calculation by any surveyor will solve this with good quality insulation and good vapour resistance. Just check on your plugs and radiators, they will need refixing, again a good quality contractor should account for this.

Floors

If you have a timber or concrete floor then we have options to insulate and look at alternative heating systems, like removing wall mounted units and turning to underfloor heating, here we can look at both water and electric systems, which opens up the Solar PV side and any storage. For timber floors the options are larger with insulation slung between the joists, but be careful to make sure ventilation is adequate to the underfloor void.

Heating System

Take some time to consider your heating system, is the boiler efficiency good and can you improve the feed to the house, Next radiators can clog up with silt, flushing the system is time-consuming, but a useful exercise. Fitting radiator temp controls are next, but before spending in this area, I would take a look and installing a complete house sensor control, to the individual radiator.

Here I want to mention alternative energy feeds such as solar, these preheat the water feed, and are excellent, and so often completely take over the water heating, but plan carefully, consider the orientation and amount of solar your house can expect to receive and its connection to the existing system.

Adding Solar PV systems might not add to the efficiency much but with the need for electric cars and battery storage improving, this needs to be reassessed on a regular basis plus with tariff feedback on adding feeds to the grid this needs to be studied for your individual area and supplier.

At this point it’s wise to take a comprehensive look at your whole house electronic needs, using your WiFi to connects radiator controls, solar blinds and generally keeping your house efficient is now not something out of the Jetsons, different house designs will need different systems, but before heading down a route to improve energy efficiency take a look at modern electronic whole-house controls, we as humans are not good at this, computers are.

Summer

House orientation

Something so often is forgotten, yet understanding where the sun rises and sets will determine your strategy on many of the items above, don't forget solar panels don't need to be on the roof, if a patch of your garden is a sun trap, consider alternative panel designs to take advantage of this.

Summer so often means warm days, and in some countries chiller units kicking in, choosing a good quality external roller blind, to shade the internal areas and cut the need to cool. If you need to use a chiller unit, again choose wisely good ventilation could be the better route, but older chiller units are often very inefficient, consider changing or re-charging the coils. With a new gas.

Above I mentioned, updating and choosing external windows, looking at the way the window opens and allows the correct ventilation for summer is a major benefit to keeping a house cool. Sash windows are particularly good at this. Understanding whole-house ventilation is a great way to understand how your individual house reacts to the sun and will offer huge savings on energy.

Flats & Appartments

Flats and apartments offer a different set of problems, with very little room to manoeuvre, however, we can do some of the above, like adding an internal high efficient mobile chiller, these need little energy, but like many of these units, they generate condensation water and need regular emptying. 

Underfloor heating can be added, but be selective, to areas where it is really needed like bedrooms and bathrooms. Electric is easier to install and a lot thinner and can be fitted under tiles in the adhesive. Not ideal for short term renters though.

Solar tint films to windows are easy to apply and reduce solar gain. 

The new home hub electronic systems offered by Google, Amazon and Apple include a lot of interesting controls, if you are allowed to, then installing radiator valves connected to the home hub is a good move.

In this area, light bulbs are an easy install, and although its not really a thermal energy upgrade, installing white noise generators make living in a flat so much quieter.

Major construction alterations like wall installation are often as not an option, so consider your upgrade carefully, if the upgrade you want is wireless and will connect to the flat wifi it gives the option to take it with you but if the alteration is a major item like window replacement and your flat has a management body, then consider many of the options above.

The consideration for resiting equipment for the flat renter who moves on is the high priority route to go for here.

I have only touched the subject, there is so much that can be done, and the new Google home developments open up more on the digital side.