If you are going to filter posts/products by taxonomies only you can use 'MDTF Taxonomies Only' widget.

- Drop the widget on the sidebar you want and press save widget settings
- Change widget title or remove it at all
- Select post type slug you are going to use
- Results output page link - change it if it necessary, or leave it empty
- Results output template - change it if its necessary, or leave it empty
- Custom reset link/url - change it if its necessary, or leave it empty
- Custom text for search results - write next for example: Found <span>%s</span> items - %s is number of founded posts, and its should be wrapped by tag <span>
Taxonomies Options:
- Check taxonomies you want to use in the searching
- All taxonomies positions is draggable, so you can by mouse set their position
- Each taxonomy in the widget has button 'Options', lets press it:
- In popup you can see some options
- Taxonomies can be displayed as: drop-down, checkbox, multi-checkbox drop-down
- Multiple checkbox drop-down - is a special mode when taxonomies terms shows as checkboxes wrapped in the html container on the site front and displayed as multi-drop-down (emulations): http://codepen.io/elmahdim/pen/hlmri
- Show as - you can show taxonomy terms in drop-down so and as checkboxes.
- Custom name/title for taxonomies - very useful feature when you do not want to show title of taxonomy as it is. Just write there text you want, or leave it empty if you want use its name as is. Looking ahead I want to say that you can show all childs of taxonomy on the same time, and each child level can has its own name, but for it you are need use such syntax: Country^Region^City. Look on the screen please to understand:
- Drop-down size - if to show taxonomy as drop-down you can set size of it (how many options will be visible on the same time)
- Show all child terms at once below - this option is for drop-down only. If you will select it - all the childs (as disabled on start) will be shown under parent as on screen in the same popup. If select them one by one, next will be enabled.
- Block max height - shows when taxonomy terms shown as checkboxes
You can set max-height in pixels, and scroll will appear. Very useful when you have a lot of terms in taxonomy!
- Toggle - you can select "close" if taxonomy terms displayed as checkboxes, so user will have to press button "open" to see them all in the search form.
- List of terms - you can see all terms for current taxonomy popup and hide any terms if you need it.
- In popup you can see some options
- Show count of posts/custom - shows near each html-element of the filter static count of posts which attached to this term
- Dynamic post recount - needs for re-count of posts combinations for each html-item. Uncheck it if you have weak server, because recount of one combination generates 1 MySQL query. More terms - more queries ...
- Hide terms where count of items is 0 - hide empty terms, which count is zero.
- Show reset button - show/hide reset button on the search form
- Auto submit form - start search after changing state of any html-element on the filter.
- AJAX items recount - if unchek "Auto submit form" you will see this option. This option is for recount combinations on the search form, but your customer still need press search button.
- AJAX items output - this is special mode to make search fully AJAXED. About this you can watch this video.
- Additional taxonomies conditions - this is the special feature in the widget if you want to set taxonomies conditions in the search form. For example you want on one page make searching of products which belongs to product_cat with term ID 96, and the filter should show count of combinations of all positions relatively to this term ID 96. You should write there next expression: product_cat=96. For more terms write condition using comma: product_cat=96,3. If you want to use more taxonomies in the same condition write something like this: product_cat=96,3^boutiques=77,88 - using special sign '^' (SHIFT+6 in Windows).
- Sort panel - if you want to use sorting for search results, select sort-panel here which functionality described here.
- Title for filter button - simple text which is written on the filter search button
That is all ...